The Genius Prince's Guide to Raising a Nation Out of Debt (Hey, How About Treason?), Vol. 2 (light novel‪)‬

It ain't easy being a bachelor...
His people might laud him for being the next great ruler, but Prince Wein of Natra has been conspiring behind their backs to live the languid life of a retired teen. Now, a major roadblock stands in his way. Ever since he won a war with a neighboring country, he's become a household name all across the land...which, frankly, sucks. And as if things couldn't get any worse, Prince Wein has just met his newest challenger: the Imperial Princess Lowellmina, who's here for a secret favor-to ask for his hand in marriage?! It's just too good to be true! Well, this genius's instincts may be spot-on, because there's something lurking behind her plan to make Wein her trophy husband...