Baazigar (1993)

Ajay Sharma, a poor but ambitious young man, is a devoted son to his widowed, traumatized, amnesiac mother. He leaves home for Bombay to fulfill the mysterious promise he made to himself and his mother. On the way he gets a lift from his childhood friend Vicky Malhotra. Ajay has secretly seduced Seema, elder daughter of business tycoon Madan Chopra, and then he meets Chopra and his younger daughter Priya at a car race in Madras. Ajay promises to marry Seema but betrays her. He then adopts the identity of Vicky Malhotra, makes the vulnerable Priya fall in love with him, and wins Chopra's trust. However, Priya refuses to believe that her sister committed suicide and keeps investigating, which forces Ajay/Vicky to murder anyone who could possibly help her discover the truth.