In-Cha no Boku ni Batsu Game ni Kokuhaku Shitekita Hazu no Gal ga, Doumitemo Boku ni Betahore desu

Misumai Youshin, a boy with a negative personality, starts going out with Barato Nanami, a prim and proper type gyaru who is at the top of the class caste. But as a matter of fact, the confession was part of a punishment game!?
And yet, Nanami, who he thought was a gyaru, was only a gyaru in appearance; in truth, she was not good with men!