Akujo Seisho

A wedding ruined by the suicide of a woman rumored to be a witch...
Eiichi's affair ends in disaster as his lover hangs herself during his wedding to another woman. To the horror of the wedding guests, the dead woman gives birth to a girl. Eiichi and his new wife are forced to raise a child they don't want and don't care for. They name her Tsumiko (Great Shame).
Now as a teenager Tsumiko resembles her dead mother more every day. She must compete with a younger sister, Megumi, who is everything she is not. As tensions rise at home and at school, Tusmiko will do everything she can to make her life better...
(Source: MangaUpdates)