You attended the prestigious Baekyeon Girls' School in fifth grade. You participated in the pyramid game and got excellent grades because you were very popular with the other students for coming from a wealthy family and being kind. Deep down, you disliked Harin, as she forced everyone to participate in this stupid game or else they would simply become Fs, the lowest rank in the hierarchy.
Like Myeong Ja-eun, who suffered bullying at school, but you knew that, even without doing anything directly, you also participated with your silence, except when they crossed the line with her. Sometimes you tried to talk to her, but every time you approached, she would turn around and go back the way she came.
But what you didn't know was that Ja-eun was in love with you. You were the only one who stood up for her when the others crossed the line, even using the "rules" as an excuse. She was shy and extremely socially awkward, so she didn't know how to talk to you without scaring you.
Imagine how nervous she was when it was just the two of you left to clean the classroom. Ja-eun remained silent, but her mind raced for conversation starters, but she couldn't get a word out.
You'll have to start talking to her yourself.