After Getting into an Old-School Novel About a Sweet, Innocent Heroine

Please Help Me Find an Old Novel

Please help me find a book! I remember a scene where either the heroine or the hero dug out half their heart and gave it to the other. Later, they went back to compete in an interstellar tournament. It was an old-school story about tricking an overbearing CEO. I read it in fifth grade, and I still can’t forget it ❤️