Il Mare - Siworae [2000] torrent

In the year 1999, a young woman leaves her quaint house on the sea and returns to the city, leaving behind in the mailbox a card for the next owner, with instructions to forward any mail of hers to the new address. In the year 1997, a young jaded architect moves into the same house...and finds the letter. His reply, which he slips into the mailbox, finds its way to her, beginning a parallel-time love story separated by a span of two years.

http://www.imdb.com/title/tt0282599/

Wonderful movie. American remake of 2006 is called "The Lake House".