Was it your hand they hacked off in Harrenhal, or your manhood? - A Storm of Swords, Chapter 72 (Jaime IX)
These words from Cersei to Jaime, spoken in anger when he refuses have sex with her in the White Sword Tower, or murder Tyrion on her behalf, are an echo of Jaime’s own thoughts after his maiming, and I would argue that they (and the many other times - especially in A Feast for Crows - that Cersei equates Jaime’s loss of his hand to his loss of masculinity) are equally as important in the deterioration of the twins’ relationship as Jaime’s mantra of sexual jealousy (Lancel and Osmond and Moonboy) and Cersei’s increasing paranoia about anyone who disagrees with her.
Westeros, of course, is a place filled with what some people call “toxic masculinity” (I prefer to call it “hegemonic masculinity” mostly because I really like Gramsci). Whatever you want to call it, this is a value system that creates an ideal of masculinity defined by certain characteristics like violence and aggression, emotional restraint/repression, physical courage and toughness, risk-taking/thrill seeking, competitiveness with other men, and a narrowly defined version of “success.” (As we see with Sam, or Tyrion, being less than physically perfect, being afraid of violence or aggression, caring more about books, etc., are all things that make you less than a man.)
When Jaime is maimed, he completely buys into the idea of hegemonic masculinity. Let them kill me, so long as I die fighting. Jaime attempts to give himself that “good” death, by fighting Hoat’s men with his left hand, a suicidal move if they actually intended to kill him. And when that fails, he gives up, willing himself to die. Without his hand, without his sword, he sees himself as no longer a man, no longer a person (why would the stars want to look down on such as me?)
And at that moment, Brienne, whose very existence challenges the concept of hegemonic masculinity (more on that later), gives Jaime a different path, a new way of looking at the world. She does it very simply - with two words: Jaime and craven.
Brienne calls Jaime by his name for the very first time right at this juncture, when he’s decided that there is no value to his life beyond his skill with a sword, and therefore he should just die. Names are important (”you have to know your name” from a different storyline, Reek doesn’t become Theon again until he rescues the false Arya, the real Jeyne), and here, Brienne is showing us (and Jaime) that she sees him as an individual, a person, not just “the Kingslayer/oathbreaker” or “Jaime Lannister, Tywin’s son, or a Lion of the Rock or any of the other shells that Jaime has built up and hidden behind all of these years. Brienne has experienced Jaime’s physicality in a very concrete way (she’s cleaned him up when he vomited after the Brave Companions gave him horsepiss to drink; she’s cleaned him when he soiled himself) and she is seeing him as a human being in pain, not as the embodiment of a role (warrior, knight, enactor of masculinity) - and this touches Jaime (who has just wondered what worth he has as a person) enough that he keeps listening.
And then Brienne asks him if he’s so craven that he can’t imagine living without his sword hand. That, of course, is exactly the problem that faces Jaime; he cannot imagine such a life.
In asking this question, Brienne is challenging another aspect of hegemonic masculinity, the idea that physical courage is the highest attainment, a man must be physically brave or not be a man (this is something Jon and the other NW boys think about Sam when they first meet him, because Sam challenges all those ideas of masculinity, but Jon does reflect that it must take a lot of courage for Sam to admit that he’s a coward.) Jaime has plenty of physical courage; that has never been in doubt. But Brienne’s words make him wonder whether he has any other kind of courage (because it will take courage for Jaime to go forward as a cripple, knowing exactly how a cripple is valued in Westeros; that is not only what Jaime’s brother has experienced his entire life, but exactly what he personally thought when he crippled Bran, when he told Tyrion that it was better to have a good clean death than to live as a cripple).) Jaime makes a choice here, to listen to Brienne, to live and go on and learn how to live as someone who no longer measures up to the idealized masculinity of Westeros. (This, by the way, is why I straight-up hate that Show!Brienne asks Jaime if he’s a “bloody woman” for “whining and crying” about losing his hand. That simply reinforces that Real Men Don’t Cry and only women are whiny and weepy and … just NO!)
Brienne’s challenge to Jaime to live, and to find other ways to be courageous, of course has an almost immediate payoff for her personally, (though that is not in the least why she says what she says). A Lannister always pays his debts. Jaime pays his debt to Brienne by saving her from rape and from death and to do so, he has to figure out how to protect her without a sword or a swordhand. The first time, he uses his wits (calling out “sapphires”) to save her from rape; then he uses his maimed and blemished body as Brienne’s shield (the body that Brienne will later remember as simultaneously godlike and corpselike, beautiful and monstrous.) It’s not a coincidence that Jaime’s most heroic moment in the series (so far) is a subversion of all of those stories where knights save maidens from monsters: Jaime saves Brienne from the bear by placing his (Lannister, and therefore precious to his father) body in front of hers, because he can’t defend her any other way.
Book!Brienne challenges hegemonic masculinity in multiple ways (she is physically tough and brave, but she also values songs and stories - a characteristic she shares with the very feminine Sansa Stark; she is skilled with a sword, but she is also gentle and nurturing when she cares for Jaime after his maiming) and that seems to make her very existence an affront to men like Randyll Tarly (perhaps the epitome of a “man’s man” and an all around nasty but of goods.) Of course we meet Wildling women and of course the Mormont ladies in the North, and to some extent, Asha Greyjoy (though she is also much more conventionally attractive and sexy than Brienne) who also fight AND do feminine things (alas, Dacey Mormont in her dress!) but they are denizens of the periphery of Westeros (beyond the Wall; Bear Island; the Iron Islands), rather than its heartlands, which are, not coincidentally, the heartlands of the chivalric system and its idealization of specific masculine and feminine roles.
I would argue as well that Jaime is more receptive to Brienne’s message because he is a lot less sexist than many of the other men in Westeros, by virtue of his lifelong connection to Cersei, whom he sees for a long time as his other self. If I were a woman, I’d be Cersei, is what Book!Jaime thinks (as opposed to the show’s “I’m not a woman, thank the Gods!” which is quite a different viewpoint!!) But his journey with Brienne, even before he loses his hand, actually shows us a Jaime who’s not particularly hung up on gender roles. Oh, sure, he says some nasty things about Brienne’s appearance (and thinks even more of them, though he also thinks early on that her eyes are “pretty and calm”) but he is also cognizant right from the beginning of her determination (the incident with Robin Ryger), her shrewd read of a situation (at the inn), and her strength and skill (the duel). He comes to respect both Brienne’s traditionally masculine attributes and her feminine ones (in this light, she could almost be a beauty; in this light, she could almost be a knight), and by the climax of their journey, in the bear pit, I would argue that he really sees her as an equal. He is perfectly fine with letting her save herself (in fact, he believes she can vanquish the bear, no problem, until he realizes that she’s essentially armed with a wooden stick, which is when he does what he can to help her.)
When they return to King’s Landing, Jaime vouches for Brienne’s honor to Loras without a second thought, even though … well, it’s a bit revolutionary to have a maiden’s honor NOT be about her virginity, but about the fact that she’s telling the truth about not killing Renly. It’s almost as though Jaime sees Brienne as a person (in the way that she saw him as a person) rather than as a flagrant breaking of gender norms!
And then he gives her his sword, the sword his father gave him, in effect ignoring the fact that Jaime isn’t a “man” by Westerosi standards any more, and there are countless layers of metaphor here, besides the very obvious sexual one. For one thing, he is giving over his role as the knight in the story to Brienne; he names the sword Oathkeeper FOR HER and she later thinks that it’s a sword fit for a hero (which she is, but bless her, she just doesn’t see that about herself.) For another, it’s a very Lannister- looking sword, so he’s also giving the true knight *his* favor (in a reversal of all the narratives of chivalric tourneys, where the lady gives the knight her favor). And lastly, he gives Brienne the sword and a quest not just for Sansa Stark but for Jaime’s own “last chance for honor ; - all three things, sword, quest and honor explicitly tied into hegemonic masculinity; all three things entrusted to a woman. (And lest anyone think I am saying that Jaime sees Brienne as brother-in-arms or whatever, I'm not. This is the culmination of a scene in which Jaime admires the fit and color of her gown, and thinks that it brings out the blue of her astonishing eyes.) Just as in his dream, he sees her both as a woman and a knight; he doesn’t think the one precludes the other, or that Brienne can't be a hero. And Brienne … Brienne turns right around with a compliment to him, rejecting some of her earliest words to him about soiling his white cloak by telling him in this scene that his cloak looks good on him. That he is suited to wear honor and vows and all the knightly things she admires (and that he knows she admires) right after Cersei has explicitly told him that he isn’t a man any more.
In short, Jaime’s road from Riverrun to Pennytree is filled with this push and pull of what it means to be a man and a quest for identity, and Brienne and Cersei are part of that. By the end of A Storm of Swords, when he writes in the White Book about Brienne's returning him to King's Landing, he has fully accepted her as a knight. He spends A Feast for Crows losing Cersei as his ideal of womanhood, and during his one all-too-brief chapter in A Dance with Dragons, he says that he looks for "innocence" in a woman - we will find out in The Winds of Winter whether Jaime sees Brienne not just as a knight, and as an "innocent", but as a woman whom he can love. I think everything in this storyline leads towards that, towards Jaime's acceptance of his own limitations, and his ability to reshape himself to be a man who can love and respect Brienne, but we shall see!