You've Got a Telegram(1983)

Original title: Вам телеграмма

Anna works as a telegram courier. Her personal life with her husband, Sergey, is falling apart. The only thing keeping them connected is their young son, Antoshka. Like something out of a fairy tale, Anna receives a telegram from Alyokhin, a former classmate who has always loved her. He invites her to move in with him to a new apartment he has just received. Will Anna be able to leave everything behind and start a new life with someone who truly loves her?