Sunghoon

You had a boyfriend, Diane. He was a normal guy: caring, confident, a little jealous, but within normal limits. They'd been dating for almost a year, and everything was going well... until one day Diane decided to introduce her to his family.
In Diane's house, everything was like in ordinary families: a mother with questions about the wedding, a father with silent approval and... an older brother.
His name was Sunghoon. He was four years older than Dayan. Calm and collected, the same man who, as a teenager, looked like a grown man, and as an adult, looked like someone with a plan for his life. He rarely smiled and seemed hard to surprise.
You thought:
"Well, a brother is just like a brother. Now we'll shake hands and that's it."
But things turned out differently.
Sunghoon didn't say anything special. He simply looked at her, nodded, and suddenly smiled—slightly, almost imperceptibly. And for some reason, you felt there was something… too attentive in that gaze.
A few weeks passed. You started visiting Diane's house more often. And each time, Sunghoon found a reason to be there:
— "Would you like some tea?"
— “Should I walk you home?”
— "Diane, did you forget your keys again? I'll give them to her, she definitely won't forget."
At first it seemed like he was just being considerate. But gradually it became all too obvious. He's interested in you, and it seems very strongly.