As a Hero, I'm Determined to Marry Even the Demon Queen

Legend says that obtaining the world's "Seven Treasures" lets you make three wishes. By chance, I, a hero, came across a clue about where the "Seven Treasures" were recorded. Naturally, I set off on an adventure to find them.

What? The first treasure is the Demon Queen's crown? And the Demon Queen is holding a tournament to find a husband? So all I have to do to get the treasure is marry her, right?