Another conversation I love, Hyunjae was worried abt yooJin and that’s how it went
Sung Hyunjae's brow furrowed slightly. His expression seemed - how to say it - troubled. I was even more curious about what it was. Was it something he didn't want to talk about? Why? I thought he didn't care about other's thoughts.
Ah... could it be?
"Is it because I showed a weak side of myself?"
[...]
He cared about me anyways. As ever. Otherwise, he would've said so out loud.
"From the start, I was and will continue to be imperfect but you know that. So if you have anything to say, just say it. I won't be able to fall apart any further at this point and I think I could accept whatever it is that you have to say."
"For some reason..."
"Yes?"
"I want to lay bare what's inside you. Everything down to the depths of you."

A conversation between hyunjae and yoojin from the novel (yoojin’s treat vers)
“You were my ideal type from head to toe.”
Strong, poised, a successful adult in society. And, well, I was jealous of your looks too. Not your face, but your height and build. The face is nice to look at, but having it myself would be too much pressure.
[...]
“And when you loitered around near me, did you think I wouldn’t develop any affection?”
[...]
His damp hair, those golden eyes beneath it, still sparkled. It was not just his appearance but his entire presence that was beautiful. He was still someone I could call my ideal type, yet it was different from before.
(Hyunjae’s treat vers )SPOILER
Hyunjae loves yooJin so much so that the only memory he preserved when he was kidnapped by crescent moon was 1.his name
2. His promise to have a date with yooJin at the aquarium
(Hyunjae and yooJin treat vers )
When yooJin said I love you to hyunjae, he confirmed it’s not for the keyword purpose, but he meant that he loves him in which hyunjae replied "I love you yooJin"
when HYJ said the keyword there was no skill window that popped out. This meant that the "I love you" was from his feelings.
"It was words to convey my feelings clearly rather than a keyword. You are precious to me and I want to help you achieve what you desire"