Welp.. She IS jealous. She wanted to stop the FL from attracting the Knight Captain's attention. She's thinking that he should stay by the temple, and since she can't be with him, no one else can. That is why she is so adamant in pushing the FL away because she is threatened. She is conscious if the Knight Captain is attracted to FL or care about her even jud a wee bit. (=・ω・=)
She a jealous biatch
Agreed! If the sponsor was a malicious person instead of our MC they would be screwed. (not even malicious, a normal person who won't tolerate being mistreated) Almost everything in the temple is built by her family and many of them have a lot of debts stacked up. Her family just needs to cut off one thing at a time and the whole religion will collapse in that area. It would be too late by the time the royal family steps in (assuming they care about this particular religion out of the hundreds)

Even though she is not a saintess, she is a priestess and her behavior is surprisingly disgusting. Well well, if i'm in her place and i'm slightly annoyed if some rich people suddenly act friendly while i'm not really know the, I will act a lil bit polite, and restrict myself to spread rumor/talk shit behind them. I mean it's just makes you looks like some jealous bastard, and ended up embarrassed yourself. Ew.