Kimi to Himitsu no Hanazono(2004)

Kimi to Himitsu no Hanazono

Having being raised by her family as a boy, Natsu simply wants to be a pretty girl. To make this wish into a reality, she moves to an all-girls school. Her roommate, Huzio, is a pretty girl - one that Natsu always wished to be. However, Huzio is actually a boy who is secretly practicing acting like a girl to take over the family business of kabuki. Quickly, Natsu and Huzio become good friends and decide to share their secret.

(Source: Operation Boredom)