Marilyn Monroe/Jean Peters
They were in a couple of films together. "Niagara" is probably Marilyn Monroe's single sexiest performance. But, boy, Jean Peters gives her a run for her money, even without smouldering the way she would in "Pick Up on South Street".
You could buy the Loomis's (Joseph Cotten + MM) as a couple of lost souls who thought at one time that they had found one another.
But even in the early 1950s you have to wonder about how a woman like Jean Peters' character felt about being married to Don Knott's dumber kid-brother.