I'll bet all my money that she for whatever reason let him hear that deliberately so that he could run away because they have something(blackmail, information, hostages, ect...) on her that makes her unable to refuse. It's either that or they write it off by using magic as an excuse because the author is clearly not good enough to write an interesting plot line where she's a willing/reluctant participant in the whole ordeal. Either way it's just going to be an excuse for the mc to mope around for a while to then have him forgive her while she falls into his arms like the generic easy female characters are in these series. Most of the time I almost don't read series where there is a female protagonist or even just love interest in general due to how poorly female characters are written.