"I really want to learn magic insofar as it will not eat my brain or otherwise have drastic consequences. I acknowledge that you are an expert at least relative to me at this time," Bella replies at once.
"What precautions exist against brain-eating?" Bella asks. "I'd like to get the risk somewhere down to car-accident-in-the-rain levels, although I'd settle for worse, since not being a sardine is slightly more important than being all out of milk and really wanting pancakes and running out to the convenience store."
"But you do magic," she says. "Or at least you've done magic."
"...A mirror? Heck, that's useful against magic and it's not even magic. What other tricks are there like that? I'll start carrying a compact," says Bella, grinning. "Low risk high return, I'm sold."
"Do they work better than standing there being a sardine? Because that's the baseline they're competing with, please remember."
She peers at the sun, and sets her phone timer to remind her to leave in fifteen minutes. It wouldn't do to blatantly flout her curfew - never explicitly rescinded - while she is pretending not to be the Slayer.
"There sure are a lotta kinds of demons," Bella remarks, returning to the book she's working through and resuming notetaking. "There might be more kinds of demons than there are kinds of beetles. Haven't they got any psychological diversity or will they really all try to eat me?"
"Why not? Mightn't they be friendly and have interesting, helpful abilities? I could rely on magic less if I had demon friends who could do anything on the order of - make force fields or send their scary guardian spirits after people who attack them or even just grow scales that are made of diamond and occasionally shed one so I could annoy the DeBeers cartel and buy a house with a really good security system." These abilities all in fact belong to unfriendly demons that she has just read about.
"Unfortunately," he says a little sharply, "the world is not divided into creatures who want to kill you and people who want to be your friends. Researchers, especially several centuries ago when most of these books were published, tend to think that the best thing to do with neutral demon species is leave them alone."