Thank you for the translation, your doing a great job.
Wow, a reincarnated into a story girl who actually read into the villains actions and noticed he liked her and did it before 90 chapters. She's still dense enough to have to ask but damn she actually asked flatly for clarity.
She really should tell him how the treads don't effect her normally. I can understand hesitance to say she knows the world through a romance novel since it sounds crazy, but at least make something up to tell him about her powers and situation. Her story of tied fates isn't to far off. She's tied to his but has none of her own. I may even go so far as guessing his own unique circumstances are why his thread is the only one her touch doesn't destroy.
I think the best walk around explanation she could use is that she's not supposed exist. (She doesn't belong to his world and wasn't in the story so it's true enough.) Since she's not supposed to exist (their) so solar's threads can't touch her and her touch destroys them. Even taking on the pain could be a form of rejection from solar. If he want's to know if she's mortal or immortal it's easy enough to wave away that it's likely but not the kind of thing one wants to test out.