Keitai Shoujo(2007)

Aida Hiro is in his second year of high school. All of his previous encounters with love went without reciprocation., but it's not unheard of for a 17 year-old-boy attending an all boys' school not to have much love experience. Still, he cannot be happy, being both unable to whole-heartedly pursue the opposite sex and fulfill his romantic curiosity. However, he is able to experience true romantic love when he encounters the Ketai Girl, "Rin".