You’re A Liar, Sir

A scruffy-looking art teacher who everyone believes is absolutely still a virgin... is actually an extremely handsome guy with a sadistic streak?! He’s the only man who’s ever snuffed the advances of the truly devilish high school girl Ichika who thinks that all men are easy marks. His name is Mr. Hazama (or as Ichika calls him, the scrufflord). In a bout of pure anger, Ichika proclaims that she is going to make him fall for her, and she gleefully puts her plans in motion to make the target of her irritation love her. But... as she gets closer and sees him without his glasses on she finds out he’s actually handsome?! And then when she asks him why he’s disguising himself, Mr. Hazama shoves her onto the bed... and he starts acting like a completely different person?! Now that she knows his secret, Ichika finds herself falling for him...

(Source: GoodReads)