Wow, thank you for clarifying that. I was confused when he said that
When did he confessed?
If you read the novel. I think it's on chapter 122-124?? That time when Eun Jiho and Yoo Chunyoung talked about Donnie, and Jiho said to Chunyoung about the confession he made when they're in middle school. Btw, their talk is during their retreat as senior high schools.
link please
https://wuxiaworld.site/novel/the-law-of-webnovels/
There you gooooo
If you're wondering what Eun Jiho meant with "Birds of a feather flock together" it's because *MAJOR SPOILER* he once confessed to Ham Donnie(Dan-I) during their middle school but she took it as a joke and that was his first rejection. That's why you can see his bitter face.
It's on the novel. I think it will be illustrated in the manhwa but I think it'll be 30-40 chapters more.