Fukumenkei Boyfriend

Masumi Itou, the most dangerous delinquent in junior high, fell in love with Rina Houjou after saving her from some hooligans. He wanted to make himself into a man worthy of her love. So he studied hard, gave up his delinquent ways, and enrolled as a studious boy in the same high school with Houjou-san. On the other hand, Houjou-san also fell in love with Ito at first sight when he bravely protected her, and she has been pining for him ever since. She didn't realize that the serious classmate wearing glasses was the delinquent she'd been looking for, until...?!

(Source: Shueisha, translated)