It could be that manhwa has diverse art styles and themes that attract a wide audience, making them constantly scan for new ones. Also, the accessibility of digital platforms makes it easy for people to browse and discover manhwa.
Hard to say. A lot would depend on the themes, art style, and how well the relationship is portrayed in the manhwa. Sometimes it could be a yes, but other times, not so much.
Yes. My Demon originated from a manhwa and has made certain changes to fit the medium of the adaptation. But the core elements and storylines are drawn from the manhwa source.
The reason could be anything from a romantic encounter gone wrong to a mystery that needs solving. Maybe it's part of a larger conspiracy or just a random act that leads to unexpected developments in the story.