The Dragon Ring (1994)

Desideria is the eldest daughter of the Dragon King and Queen and heir to the throne and the Dragon Ring. If she marries a prince that is. When she finds her prince however it turns out to be a rebel prince. When her father finds out she tries to help the prince escape he decides to let all the princes in his conquered kingdoms fight in a tournament for her hand in marriage. Meanwhile her jealous adopted sister tries to get rid of her.