Hannune Banhada! Season 2

Kang Han-Se and Ban Ha-Da have known each other ever since childhood. They are close enough to sleep in the same room together at their current age.

"Three men for you," Kang Han-Se's mother tells Ban Ha-Da, on the day of graduation. As soon as Ban Ha-Da's life as a high school student starts, her love life begins as well.

(Source: Korean publisher, translated))