Laura Hunt (Gene Tierney) and Detective Mark McPherson (Dana Andrews) exchange their first kiss at her door in the closing moments of the 1944 20th Century Fox film Laura. He had just confirmed that his suspicions about the murderer’s identity were correct, and was telling her not to answer her phone, get some sleep, and “forget the whole thing like a bad dream,” and that he would call her in the morning.
MATTHEW'S ISLAND 
Dana Andrews, in (perhaps) “The Iron Curtain” (1948)?
Dana Andrews is an excellent guess. I think he’s actually in a military uniform if that’s any clue as to what picture this was from.
Laura Hunt (Gene Tierney) and Detective Mark McPherson (Dana Andrews) exchange their first kiss at her door in the closing moments of the 1944 20th Century Fox film Laura. He had just confirmed that his suspicions about the murderer’s identity were correct, and was telling her not to answer her phone, get some sleep, and “forget the whole thing like a bad dream,” and that he would call her in the morning.
Such a great movie! Definitely one of her two best films. Haven;’ seen it a while though.