The Girl I Saved on the Train Turned Out to Be My Childhood Friend

Chikan Saresou ni Natteiru S-kyuu Bishoujo wo Tasuketara Tonari no Seki no Osananajimi datta
美少女を助けたら隣の席の幼馴染だった

Source

The Girl I Saved on the Train Turned Out to be My Childhood Friend
Chikan Saresou ni Natteiru S-kyuu Bishoujo wo Tasuketara Tonari no Seki no Osananajimi datta· 痴漢されそうになっているS級美少女を助けたら隣の席の幼馴染だった
novel

As children, Ryou Takamori and Hina Fushimi were thick as thieves-but while Hina grew more beautiful and popular, Ryou faded into the background as a loner, and the two drifted apart. That is, until the morning Ryou saves Hina from a groper on a train and unwittingly reminds her how close they used to be. Now Hina is smitten-if only Ryou weren’t so oblivious! (Source: Yen Press)