The Cranes Are Flying (movie, 1957)

Veronika and Boris come together in Moscow shortly before World War II. Walking along the river, they watch cranes fly overhead, and promise to rendezvous before Boris leaves to fight. Boris misses the meeting and is off to the front lines, while Veronika waits patiently, sending letters faithfully. After her house is bombed, Veronika moves in with Boris' family, into the company of a cousin with his own intentions.