The importance of honouring your promises is one of the ideas conveyed by this story. The princess is reluctant since she does not find spending time with a frog appealing, but the king pushes. "What thou hast promised, thou must fulfil," her father said.The girl is obedient only unwillingly. Father clearly knows best, for she would have never found her prince if she hadn't followed her promise. It provides the message to the reader that when you keep your word, nice things happen.