Haitoku no Kyoukai

Overview

A cool, overly serious and straight faced woman, Kisaragi Miyuki, gives off an unapproachable aura to her students. She is very stern, doesn’t take a joke well, and distances herself whenever possible. There is a rumor however that she is the complete opposite in her private life, and supposedly when not at school, she’s a clumsy airhead. This rumor catches the attention of one of her students, Miwa Itsuki, who has a problematic personality that gives him the desire to tease woman with faulty characters like his sensei. When he catches Miyuki shopping at the convenience store which he works part-time, he can’t hold back his sadistic tendencies any longer…

Source: AniList