Luck of the Draw: The Chronicles of Xanth (Xanth, 36)

Bryce is summoned to Xanth as part of a wager between the Demons Earth and Xanth. To his surprise, he has left behind his home and family and eighty-year-old body forever, in exchange for youth and magic…and a quest. He must court and marry Princess Harmony, who is anything but willing to be courted!
Luck of the Draw is Piers Anthony's thirty-sixth pun-filled adventure in the magical land of Xanth.