Cheers (1982)

S5E1 The Proposal

We discover that Sam's phone proposal from the previous episode was directed at Diane. However, Diane worries that Sam might just be rebounding after his split with Janet. She suggests he propose again in a more romantic setting. When he finally does so aboard a boat, she surprisingly declines, prompting Sam to playfully make her walk the plank. Later, Diane admits she does want to marry him, but by that point, Sam has pulled back his proposal.