I do not understand the point in this thread.
The reason I originally asked what is wrong with them going to korea, is because I do not assume you guys are religious, so I would assume your main concern is them partying or doing haram in korea
From that angle I have found most women yes even white women just want to travel explore new places and eat new food and have fun with their friends,they are not getting up to nasty stuff like sexual things or even drugs or whatever, unlike alot of men who like to party and have sex, so from that angle most women are innocent and their travelling is not evil therefore you should have no concern, I know alot of xalimos who never could afford travelling when younger and noone is going with them to another country for a university paid vacation with their friends so they go anyway so they can have fun and not miss out, no bad intentions there.
If you are a religious brother who is strict on wanting their wife to adhere to Islamic rulings to the point that if your potential travels without mahrams and is fine with it then I would say depending on her other redeeming factors and if she is willing to not go on those trips anymore then it is not a dealbreaker, if she does not care about deen that much and will stil go on those trips I would say it is fine
Then again most of you guys are not religious enough to be demanding stuff like this cos u don't even lower ur gaze speak good words dont backbite be good to your parents have good character etc etc so u demanding that from a women is stupid.
Me personally if my potential went on a trip in the past unless she regrets it and says she won't do it without a mahram again it is a dealbreaker, but it does not mean she is a bad person