The White Mage Doesn't Want to Raise the Hero's Level Vol. 1 (manga)

Irie Izumi has been summoned to another world to fulfill his heroic destiny! He quickly meets and forms a party with Level 20 white mage Shina, who falls in love with him at first sight. When Irie succeeds in his quest, he will be transported home–but Shina isn’t about to let her “Lord Hero” get away so easily! What’s a girl to do, except dress so lewdly that even a great hero of destiny can’t pay attention to the battles before him and can’t level up!