If Kino is obsessed with being a man, he is equally obsessed with keeping Juana in her place as a woman. And Juana doesn’t seem to mind. She accepts that she is to be passive, submissive, and deferential. Yet, despite her passivity, Juana manages to function as a pillar of strength for her husband. Kino himself comments on her resolve and her ability to persevere without food or rest. She’s like the Super Woman of housewives.
Kino had wondered often at the iron in his patient, fragile wife. She, who was obedient and respectful and cheerful and patient, she could arch her back in child pain with hardly a cry. She could stand fatigue and hunger almost better than Kino himself. In the canoe she was like a strong man. (1.22)
Not only is she strong, she's also got her head on straight. She acts as the voice of reason throughout much of the
novella. Her prediction that the pearl will destroy their family is of
course quite accurate, and her careful advice to Kino (which he
consistently ignores) becomes a routine gig in the text. She's a wise woman.
(Or is she? As we discussed in "Symbols, Imagery, Allegory," her claim that the pearl is evil isn’t quite accurate. The pearl isn’t evil; the greed of men that desire the pearl is evil.)
She's also hyper-observant. She knows what Kino is thinking even when he doesn't say anything (or even when he's, um, beating her when she tries to throw his pearl into the sea):
This meant certain things to Juana. It meant that he was half insane and half god. It meant that Kino would drive his strength against a mountain and plunge his strength against the sea. Juana, in her woman's soul, knew that the mountain would stand while the man broke himself; that the sea would surge while the man drowned in it. And yet it was this thing that made him a man, half insane and half god. (5.5)
She knows that her hubby is losing it, and that, as a man, he was going to "break himself." It's a testament to her steadfastness—and to her adherence to traditional gender roles—that she allows him to just be a man even though being a man means being "half insane and half god."
After Coyotito dies, however, Juana and Kino seem to break away from these once-rigid roles. They walk back to La Paz side by side, not with Juana following behind as she had before:
The two came from the rutted country road into the city, and they were not walking in single file, Kino ahead and Juana behind, as usual, but side by side. The sun was behind them and their long shadows stalked ahead, and they seemed to carry two towers of darkness with them. (6.100)
Kino even shows deference to his wife when he offers the pearl for her to throw away (although that may be just his way of apologizing for beating her up earlier).