Amir is the main character of the novel, Kite Runner. He is characterized as a selfish coward for most of his youth. He also desperately wants the affection of his father Baba, but he feels that he does not have it, because he is so unlike him. Baba is a man of courage, conviction, and principle. Amir is none of these things. Hassan, who is a servant boy, is much more like Baba. So, Amir has mixed feelings when it comes to Hassan. In one instance, he watches Hassan get raped and does nothing about it. And this guilt lingers. When Amir is finally in America, he is much of the same - a selfish young adult. However, he comes to redeem himself in the end, as he faces his demons and becomes a selfless man. He adopts Sohrab and faces Assef with courage (and is even beaten by him). Hence, we a transformation.
When it comes to Soraya, we see a transformation as well. Soraya is the daughter of Afghan general Taheri and his wife. However, she is "damaged goods," because when she fled as a refuge she lived with a man that was not her husband and was no longer a virgin. In this society, this was a huge taboo. Her healing process began when Amir still loved her and wanted to marry her. This also brought complications, because she could not bear children. So, when they adopt Sohrab, the healing process is complete.
In light of the above, both are broken people, bound by their past, and find redemption in each other and an adopted child.
Amir and his future bride are similar in many ways, particularly in how they have grown up in the shadow of their powerful fathers and how they are both "damaged goods." Amir cannot sleep at nights because of the guilt he feels for his past sins against Hassan, and for how he has been unable to make Baba proud of him. Soraya's reputation was ruined among the Afghan community in Virginia after she ran away with her boyfriend, and she still feels bullied by her father; and like Amir (who feels Baba blames him for causing his mother's death), she feels guilt for causing her mother's stroke. However, Soraya's confession to Amir concerning her past indiscretion seems to cleanse her own guilt: Amir wishes he had the courage to do the same, but his own guilt only grows when he remains silent.
I envied her. Her secret was out. Spoken. Dealt with... I suspected there were many ways in which Soraya Taheri was a better person than me. Courage was just one of them.
While Amir seems to be at peace with the way his relationship with Baba had ended, Soraya is still at odds with her father; yet she has a loving mother to fall back on, unlike Amir. The couple had only the most minor of conflicts:
She slept on the right side of the bed, I preferred the left. She liked fluffy pillows, I liked the hard ones. She ate her cereal dry, like a snack, and chased it with milk.
Soraya slept well, while Amir often retreated to the balcony to battle his insomnia. The two disagreed on whether to adopt after discovering that Soraya was infertile. And the "emptiness in Soraya's womb" caused a rift between the two.
It had seeped into our marriage and... in the darkness of our room, I'd feel it rising from Soraya and settling between us.