You chose: Arabella should marry someone else
While in the novel, Arabella marries Glanville, there is no reason why she couldn't have ended up marrying someone else. However, given her belief in the romances, becoming involved with someone else could be quite dangerous for her. Her misconceptions of who is good and who is bad, who has her best interests in mind, and who people really are (not everyone is a prince in disguise) could very easily lead her into a dangerous marriage with someone who isn't actually interested in her for good reasons, or someone who simply runs out of patience eventually for her beliefs and misconceptions about the world.