Regis knows it's an illusion. He's only ever seen Princess Charlotte from afar; only heard her voice when she spoke to a crowd. Sure he's good at reading people, but he knows she of all people will be wearing a perfect mask.
The problem is he's in love with the illusion, and it's not going away.
So he strikes out on a quest: win the fighting tournament held every year, where she gives out the prize, and hypothetically—just hypothetically—he can forfeit the monetary winnings and instead ask for a week to be close to her, to get to know the real her, and break the illusion once and for all.