Third Finger, Left Hand

Third Finger, Left Hand is a 1940 American romantic comedy film. A woman pretends to be married to fend off wouldbe suitors and jealous wives, then regrets her deception when she meets an artist.

At the nightclub, a drunken acquaintance spots Margot and mentions her husband, forcing Margot to improvise and tell Jeff that it was merely a passing infatuation in Rio de Janeiro. He believes her at first, but then some inconsistencies in her story cause him to check up on her he concludes that there is no Tony Merrick.To teach her a lesson, he shows up at her family mansion and announces to her father Raymond Walburn, younger sister Bonita Granville, and butler Halliwell Hobbes that he is Tony. He is welcomed with open arms. Margot has no choice but to go along with the deception. ........

Source: Wikipedia