Mr. Straightforward (2010)

Original title: まっすぐな男

Matsushima Kenichiro is basically a straight guy because he hates dishonesty. He is an employee at a medium-sized building firm and works in design. However, he is inept when it comes to love. Kenichiro's destiny changes after he meets Kurita Narumi, an audacious, self-centred impish female. He becomes serious about leading her back to the right path which she finds interesting. While getting pushed around by Narumi, who is the exact opposite of him, Kenichiro learns about her way of doing things and way of life. He is stimulated by her and gradually gets attracted to her... Before long, he starts to look at a new self and at the things he had believed were correct, maturing into a more upright man.