I'm looking for a Manhwa (i think it's a webtoon but I could be wrong...) in which the story centers around a girl who's locked up in a house/room. The main character is a boy who mistakenly entered the place and met the girl. They befriend each other. The girl is often "used" for sex by the neighbors. Some,including the boy, are obsessed with her.
IIRC, the girl doesn't grow old, despite everybody around her does..

I remember the story's premise but no luck Googling it.. thanks before!

I think it's Hwaja

Thanks, Breizh!
It's Hwaja!