That much debt for a single necklace? Do they not have any usury laws? Even if they don't, that guy should watch out. It's a feudal society with a Duke/Duchess, if she wanted to she could just say "this debt is annulled, if you don't like it, there's a prison cell with your name on it."
Still, I'm loving this story. You can put it down on record, it's hall good, this greenish crown-like thing.
@keks503
I assume after deciding to send him to the academy, there was still some time where they were sending letters to start enrollment, getting things packed, etc. Even if it were just a few days or weeks, he might have noticed a difference if she were tormenting him every day.