Answer:
Amir envied Soraya for her ability to be open about her past life and accepting it gracefully, freeing herself from that guilt and also for being a better person than he is.
Step-by-step explanation:
"The Kite Runner" is Khaled Hosseini's first novel which deals with the issues of migration, guilt and redemption. Set across the backdrop of the fall of monarchy in Afghanistan, the rise of the Taliban and the migration of people to America and other places, it tells the story of Amir.
Amir and his father Baba had illegally migrated to America. Before all of this, Amir and his family had been living peacefully in Afghanistan, flying kites with his best friend Hassan, the son of his father's servant and from a inferior race. But an incident where Hassan had sacrificed his body and dignity just to save a kite for Amir led to him getting raped by some boys. Unable to acknowledge the incident and feeling guilty, he distanced himself from Hassan. Later, when they are in America, and he met Soraya, he envied her for her ability to free herself of her guilt. She had also been having a rather unconventional past, but she has accepted. She had become a better person, accepting her life as it is. This is what Amir is envious of.