@NinkNikkita I think it'll make more sense if they used 'lady'. But because this is a translation from Korean, they used 'princess' as it is the closes translation from Korean to English.
Liking him is not wrong, but to force herself in to be the legal wife while he already have a wife is wrong. Well, I can't say that we don't thank her though. If she didn't come, then Luxia wouldn't hosted the original Luxia, and then she wouldn't get her karma.