What is the name of this movie?

I watched this movie long time ago, about 5 years approximately. I don't remember much , a few scenes only. I think that was the story of two people ( girl and boy ) who met and fell in love, but after a while they break up. After a few years she returns to the city and accidentally meets him. In those few years when they were separated he was waiting for her. And before that, they buried a letter in the park ( as I recall ), and later dig it up and I remember the time that has passed. And there is one scene that I remember : the two of them were walking through park and there was a man with a gun that wanted to kill someone cause he was desperate because his girlfriend left him and she tried to calm him down and tell him something like 'you do not want to die , nobody wants we all I want to see the end of the story'. That is all I can remember. I don't even know if this is exactly what happened. But I know that I really liked film, so please help.:)