Serim's Golden Rule

Everyone's terrified of Se-Rim Han. Word is, she's a gangster. So of course Seung-U Kang, the ultimate golden boy, ends up with her in the school’s mentor-mentee program. He decides the only way forward is to become her friend, but the closer he gets, the less anything makes sense about her. What starts as a simple assignment soon turns into something neither of them planned, a dangerous romance between a girl who lives like there's no tomorrow and a boy whose entire life has been meticulously mapped out.

(Source: WEBTOON)