It's important to understand that Soraya's sin is very much a question of the point of view. For one, the reader could be unsure of what exactly her sin is . It could be either the fact that she ran off with a man when she was young and they...
It's important to understand that Soraya's sin is very much a question of the point of view. For one, the reader could be unsure of what exactly her sin is. It could be either the fact that she ran off with a man when she was young and they didn't marry. That kind of a life isn't considered acceptable for an Afghan woman, as her father kept reminding her. Or it could be that Soraya's actions caused her mother to have a stroke, since she didn't think her behavior to be appropriate either.
The issue of a sin is difficult, therefore. Soraya herself feels guilty only for the part she played in her mother's stroke, although she does also understand that she can't be responsible for someone else's mental state. It's not up to a person to act according to everyone else's moral standards to preserve their health, but since it was her mother, Soraya naturally has regrets. Concerning the rest, she doesn't agree, given that she vehemently disapproves of the way women are treated in her society. In short, Soraya views her sin as something that has been bestowed upon her, rather than something that she feels herself. She brought shame to her family, so she kind of assumes everyone sees her through that lens, but Amir does not. He has burdens of his own and doesn't care about her past.
Soraya's redemption is a complicated matter, due to all that. She atones by admitting her mistakes to Amir, by caring for him and Baba, and by providing Sohrab with a loving family. It's just the question of whether she really has anything to redeem or not. The fact is that Soraya is troubled like Amir is, but unlike him, she actively makes an effort to be better for it. She shows kindness and understanding, just like she'd like to be understood. In contrast to Amir, Soraya finds redemption for sins imaginary and real by being a good person without being prompted, while her husband needs a little push and her example to pursue his own.