The Prince and Betty.

Young American John Maude is forced to find a job when he falls in love with society girl Betty Keith. He accepts a sudden offer to go to Mervo, a tiny island country, where he is hired by Benjamin Scobell to pose as the lost prince of Mervo as an attraction to bolster the Mervo casino as a rival of Monte Carlo. Scobell also wants John to marry his stepdaughter, who turns out to be Betty. When Betty accuses John of being simply a shill for a gambling house, John closes the casino and tries to stage a revolution to make Mervo a republic.