Uli Museun Saiya?

Se-Hee and Yeon-Woo are childhood friends who have known each other since childhood, but Se-Hee actually has a crush on Yeon-Woo. However, Yeon-Woo's attitude has become strangely cold since the start of her unrequited love. As a result, Se-Hee decides to give up her hopeless unrequited love. Seo-Jin, her transfer student, appears in front of Se-hee, and the two become closer...

(Source: Naver, translated)