This is the part I hate the most in this manga. Imagine you being in love with another person. All of a sudden you two get transported to another world. Your partner loses their memory and falls in love with someone else, leaving you heartbroken. This feels like watered down NTR... Not that I dislike Natsu, but the way these two's relationship turns out really leaves a bad taste in my mouth. I don't know what she sees in Kenyou, either.