Anandam (2001)

Kiran (Akash) and Aishwarya (Rekha) are neighbors for 20 years in Hyderabad. They study in the same college and hate each other immensely. Aishwarya's parents shift to Ooty.

At her new home, Aishwarya happens upon an unopened greeting card addressed to Deepika (Tanu Roy). Aishwarya comes to know that Deepika was the room's previous resident. In a tragic twist, Deepika committed suicide because her lover Vamsi (Venkat) did not return after going to Hyderabad.

Aishwarya opens the letter addressed to Deepika and realizes that Vamsi wrote it. It's a sensitive letter written by Vamsi explaining his feelings towards her. Aishwarya does not want to disappoint Vamsi by revealing that Deepika is no more. She starts writing letters to him in red light, pretending to be his beloved Deepika.

Interestingly, on the other side Kiran ends up being the one to reply to all of Aishwarya's letters on behalf of Vamsi, as Vamsi dies in a tragic accident in Hyderabad. The rest of the film is about how these two people come to know about the real story and turn the their hatred into love.