«Sister of My Heart» by Chitra Banerjee Divakaruni

Anju is the daughter of an upper-caste Calcutta family of distinction.
Her cousin Sudha is the daughter of the black sheep of that same family.
Sudha is startlingly beautiful; Anju is not. Despite those differences,
since the day on which the two girls were born, the same day their
fathers died-mysteriously and violently-Sudha and Anju have been
sisters of the heart. Bonded in ways even their mothers cannot
comprehend, the two girls grow into womanhood as if their fates as well
as their hearts were merged. But, when Sudha learns a dark
family secret, that connection is shattered. For the first time in their
lives, the girls know what it is to feel suspicion and distrust. Urged
into arranged marriages, Sudha and Anju's lives take opposite turns.
Sudha becomes the dutiful daughter-in-law of a rigid small-town
household. Anju goes to America with her new husband and learns to live
her own life of secrets. When tragedy strikes each of them, however,
they discover that despite distance and marriage, they have only each
other to turn to. Set in the two worlds of San Francisco and
India, this exceptionally moving novel tells a story at once familiar
and exotic, seducing listeners from the first page with the lush prose we
have come to expect from Divakaruni. Sister of My Heart is a novel destined to become as widely beloved as it is acclaimed.