Amaanat

Amaanat is a 1977 Bollywood film directed by Shatrujiit Paul. The film stars Manoj Kumar, Sadhna, Balraj Sahni, Mehmood, Asit Sen, Aruna Irani.

While on the train a man asks Suresh to take care of his wife and baby girl who are travelling alone for first time. Suresh agrees. The train meets with an accident and the lady dies. Suresh takes the baby entrusted in his care and starts looking after her as his daughter.Sureshs wife has been left to fend for herself and her son Deepak. She starts working as a maid to earn a livelihood. Her employer offers to adopt the son and provide him with an education and clothes to wear and food to eat. She agrees to leave her son in his care so as to give him a good life. ........

Source: Wikipedia