Responses
I think its Empress of Another World.It has the same scene that you describe but not sure tho.
http://www.mangago.me/read-manga/empress_of_another_world/
I think this is the one you're talking about although the part that you described was kinda towards the end of the story.
Empress of another world ? This part somewhat happened near the end.
Okay, thank you all :3
All I remember is, that its a isekai shoujo, where the girl mc get thrown into the new world through a portal. After she get to know the male mc and possibly spend a night with him, the portal opens up again in the same place (forest?). The male mc realizes that the girl is gone and rushes to the portals place, thinking that the girl has gone through. However, she is just sitting in front of the portal with out going through. Any clues what this (possibly) a webtoon is?