Mere Sajna (1975)

Ratan (Navin Nischol) is a criminal working for Master (Ajit) and his wife Sona (Helen Jairag Richardson). He goes home to his mother's funeral and meets with his childhood friend Kammo (Raakhee), who is mentally incompetent. Her wealthy father arranges her marriage to Ratan, with the hope that she will become normal after marriage. Initially, Sona is disappointed that Ratan will marry, as she has a crush on him. But once it becomes clear, that Ratan wants to marry Kammo for her money, both she and the Master fully support it. They also encourage Ratan to kill Kammo soon after marriage. Ratan starts caring about Kammo and she becomes more normal. Ratan wants to break free of Master and Sona, but they won't let him. Master's henchmen kidnap Kammo and Ratan rescues her, and Master dies in the climatic fight.