Many a true word is spoken in jest
Many a true word is spoken in jest.and There's many a true word spoken in jest.
Prov. Just because something is said as a joke, it can still be true. Fred: Why did you make a joke about my being stingy? Do you really think I'm cheap? Ellen: Of course not, don't be silly. It was just a joke. Fred: But many a true word is spoken in jest.