Go! Baajinaru Hanayuki

From Nekohana: It all starts when Tomoe's hair gets caught in Kouga's button. As if by a red string of fate, they're tied together. Through a twist of that fate, Tomoe is forced to work in a house of prostitution lead by the yakuza, and who might be one of the yakuza heads, but Kouga. Funny and dramatic, but more innocent than you think.