Misaki-kun wa Kouryaku Chara ja Nai

This is the world of gal games. The mission of the best friend character, Misaki Izumi, is to support the main character, Kihara Haruta, in conquering the heroine... but for some reason, Kihara himself is planning to conquer Misaki himself! "Become the heroine while remaining a boy!" Friendship? Love? A happy, heart-pounding comedy about a boyish girl!!

(Source: Shinchosha, translated)