I have a question about the pearls - I thought they were just an illusion, but Vanja keeps talking about their effect on people, especially Emeric, who often seems to have his legs swept out from under him.

Do the peals have some effect beyond an illusion of beauty that makes people take notice? Emeric implies they don't work on him the way Vanja expects/they do for others. What do they do to him? What does he see?

So there are two concurrent things playing out with the pearls! Spoilers under the cut.

1: The pearls don't just physically transform the wearer, they essentially are souped-up pretty privilege. If you are romantically attracted to women, you'd have a crush on the wearer. If you aren't romantically attracted to women, you'd want to be their companion, confidante, accomplice. It doesn't override every other emotion, it just puts a thumb on the scale.

2: Our junior prefect has two things working for him. First, he has the glasses that show enchantments, so he knows what effect Vanja expects the pearls to have on him. And second, he's demi, so at first, all he gets is the inclination to be friends. In the first act, he's playing into Vanja's expectations so she underestimates him; in the second, he's mostly neutral to her in the pearls. In the third act, you can actually pinpoint when he's officially caught feelings, because Vanja puts on the pearls and is like "wow he looks like he got run over by a mack truck, never seen him do that face before............. WELP IT HAS NOTHING TO DO WITH ME SURELY."