The Girl I Saved on the Train Light Novel 1

While on his way to school one morning high school second year Ryo Takamori saves his childhood friend Hina Fushimi from a sexual harasser on a crowded train. Although the two are practically opposites in appearance and popularity, not to mention the fact they haven't spoken since middle school, Hina finds herself smitten with the oblivious Ryo. A frustratingly sweet, zero stress romantic comedy!