Gouin Dakedo Yasashikute

From Fantasy Shrine:
Taking care of his homeroom teacher, Wakasa-sensei, the kindhearted Kakeru is the only person who knows the outwardly charismatic teacher is in truth, a bully! Whenever they are alone, Kakeru tries unsuccessfully to evade Wakasa’s advancements. However, Kakeru couldn’t help noticing Wakasa’s tenderness at unexpected moments. And then, at the start of the 3rd year in high school, a new teacher from Wakasa’s past and a new student arrive…