He Can't Be This Dumb! 

Renowned for its exclusivity, only the children of Korea’s elite can attend International Island High. But when Kang Do-Ha, an ordinary girl from an average family, is given a lucky chance to enroll, she’s thrust into an unfamiliar world of money and power. Despite trying to fly under the radar, she somehow ends up in the same dorm as Rowoon, the most popular guy in school! He seems to have it all, but when it comes to girls, he’s completely clueless. Can Do-Ha teach him how to win a girl’s heart? (Source: Tapas, edited)