Here are some key points to consider:
* Early Episodes: Joon-hyuk initially sees Se Kyung as a quirky and annoying younger sister figure. He's often annoyed by her childish antics and doesn't pay much attention to her romantic interests.
* Growing Affection: As the show progresses, Joon-hyuk starts noticing Se Kyung's positive qualities. He's impressed by her kindness, strength, and resilience. He also finds himself drawn to her innocent and energetic personality, which contrasts with his own cynicism.
* Jealousy: One clear sign of Joon-hyuk's growing feelings for Se Kyung is his jealousy when she develops crushes on other men. This highlights his possessiveness and his growing desire to protect her.
* Conflicted Feelings: Joon-hyuk struggles with his feelings for Se Kyung, especially as she begins to show interest in him. He tries to deny his attraction, but his actions often betray him.
* Openly Expressing Feelings: While he never directly confesses his love for Se Kyung, there are several moments where he subtly reveals his affection. For example, he expresses his concern for her well-being, or he makes an effort to spend time with her.
In conclusion, Joon-hyuk's feelings for Se Kyung gradually develop throughout the show. It's a journey of self-discovery and acceptance for him as he learns to appreciate her for who she is. While the exact moment of his attraction is debatable, it's clear that his feelings for her grow stronger as the show progresses.