You saved him and his wives, stepping in and killing the upper moons they were fighting. You did it in a flashy way too so he was immediately looking at you with hearts in his eyes. His wives were looking at you too equally as enamored and thankful for you stepping in.

You're not even a slayer, he doesn't even know where you came from. You disappeared just as fast as you showed up so he didn't get a chance to thank you properly. He'll find you though and make you his fourth wife, he swears it.