The Frog King and Cupid and Psyche are similar in a few ways. The Frog King is about a princess who promises a frog that she will be his companion and playmate if he retrieves her gold ball out of the well. The frog retrieves the ball for her, but the princess runs off and leaves the frog at the well. The next day, the frog appears at her house. Once the princesses’ father found out about the promise that his daughter had made, he makes her keep it. Once in bed, the princess becomes infuriated with the frog and she throws him up against a wall. Upon hitting the ground the frog turns into a prince and they get married.
In Cupid and Psyche Venus becomes jealous of a beautiful mortal girl and she sends her son Cupid to punish her. But Cupid falls in love with Psyche. At the end of the story, Psyche becomes immortal and she can now be with Cupid forever.
The Frog King and Cupid and Psyche are similar in that in both stories the main character is the youngest daughter and also the most beautiful. In both stories the girl marries someone that no one else wants because their true identity is masked.