Konyaku Haki da, Hatsujou Seijo.

Monster-fighting priestess Monica's impressive powers earned her an engagement with the crown prince, but... those powers come with a downside, arousing anyone affected, including herself! When the prince finds out, their engagement doesn't last long. While news of the "indecent" holy woman spreads throughout the land, an unexpected connection from her past approaches Monica for help: he needs her powers, and the rumors don't seem to bother him. His name is Richard, and unbeknownst to Monica, he is also a prince... (Source: Tokyopop)