Movie based on 1940's, war and romance

Very probable on WW2, a young man meets a girl in some dance hall. They eventually get engaged. The couple agree not to enlist him to the Army because that'd separate each other. The most solid scene I have in memory is when he visits her house and knocks to tell her that he'll go to War anyway. Then they argue for a minute and he leaves running. But just three seconds later he runs back and kiss her. One more thing I remember is that he grew up at the rural and worked along with some guy that was pissed off since the boss paid this man less once..