I actually think she has never seen how a real loving relationship works. I think she has trust issues and the only realnloyalty she has seen is because of master servant relationships. You have to have power over someone to make sure they don't betray you or leave.
Looks like the current group is not translating this manga anymore so for anyone curious the raws can be found in the Mangadex links section, it currently is at chapter 7 and you don't even need to be able to read the dialogue to understand what's going on since the story is so simple
MC and FMC trip and accidentally kiss during a summer festival