Shiramine doesn't swear. It does not conform with her character. At least that is what i imagine. So her saying "what in the he**" is a bit farfetch even if she is taken aback by the rumors.
Firmly believe Manga 🇯🇵 & Manhua 🇨🇳 are far superior than Manhwa 🇰🇷 in term of plot quality and creativity, artwork & humor = basically everything.