Three's Company - Season 5 Episode 13
Father of the Bride

Cindy is flourished with the wealth of an older man who wants her to be his bride. Her persistant refusal to wed him doesnt seem to be enough, so Jack and Janet try to figure out a way to discourage him. They soon find themselves tempted by his generous promises for the future, before coming to their senses and rescuing Cindy from her worst nightmare.