Life is harsh to both Mariam and Laila, but they manage to find ways to stand up to cruel fate and see some beauty in life. This shows that they are both strong in spirit, even if they don't have much in common otherwise. Mariam is an illegitimate child, having grown up with a bitter mother and an absent father whose love she desperately craves. Laila, on the other hand, has a supportive father and a distant mother. Growing up, she was allowed much more freedom, and she is therefore considerably more headstrong than Mariam.
Both women end up married to Rasheed, however, and have to share the same trials and tribulations of being his wives. Initially, their contrasting backgrounds and beliefs make them wary of each other. Mariam, who has never had much to call her own, becomes jealous of the younger woman. Rasheed is not a good husband, but before Laila came along, at least he was only hers. With the new wife, Mariam feels that once again she is pushed to sidelines, especially when Laila's pregnancy is revealed. The pain Mariam has felt after her miscarriages quickly turns into antipathy against Laila. She, in turn, can't bring herself to trust Mariam.
It's understandable why their initial reactions to each other are what they are. Mariam, the more conservative of the two, feels threatened by a young rival and her liberal ideas. Laila, being more educated and rebellious, can't find a common ground with her. It's only after they've gotten to know each other, after they've both suffered under Rasheed's hands, that they come together. Laila's example opens up a new world for Mariam, and in a way, she becomes a stepmother to her and to her children as well. Saddened by her own inability to have children, Mariam finds comfort and redemption in protecting Laila's. She, in turn, finds a motherly figure in Mariam, an example of kindness and strength that emerges from Mariam's true core after they become united against Rasheed. In this way, the women help heal and support each other, becoming friends, although many readers have deemed it more like a mother-daughter relationship.
Ultimately, they become each other's saviors. Mariam, who wanted nothing more from life than to be loved, to be important to someone, ends up giving her life for Laila and the children. She does so happily, knowing that she means a lot to them—that instead of dying a sad little orphan, she leaves the world
as a friend, a companion, a guardian. A mother. A person of consequence at last.
And Laila, who wanted to be free, gets to be free through Mariam's sacrifice. With Rasheed gone and Mariam refusing to let Laila be dragged into the trial, she can finally be with Tariq and start a real family with him and the children. In addition to their own personal liberation, the two women's courage also brought about a better life for Laila's children, who could grow up with caring parents and hopefully be the seed of a brighter future.