"Ah, just coffee, thanks," you say, taking one of the three.
"Yeah, same for me," says Hope.
Vivienne shrugs, taking the third coffee for herself. "Alright, alright, I get it, the idea of drinking a random potion from a witch you've just met makes you nervous, right? Sometimes I think the ones who just slip them in secret have the right idea, but that just seems wrong, y'know? Plenty of willing subjects out there."
You nearly choke on your coffee as Vivienne mentions slipping the potions in secret, but you feel fine for the moment. Well, fine aside from being nervous.
Hope has yet to drink hers, and gently says, "Well, to be fair, it might help, just a little, if you'd tell them what your potions do."
"Aw, but that's no fun," says Vivienne. "Although, I guess it might be a little more productive." Then she takes a sideways glance at you. One that lasts a bit longer than it should.
"...Can I help you?" you ask, nervousness getting the better of you.
Vivienne pauses, but then lets out a breath. "Okay, I may have lied just a little bit."
"What do you mean?!" you ask, suddenly panicked. "What did I just drink?!"
"Relax, relax, it's just coffee, honest. Um, mostly honest," says Vivienne. "The truth is, I did enchant it to let me know if whoever drank it could learn magic. I swear that's all I did to it, though."
"...Wait," you say. "Are you saying I could--"
"I am," says Vivienne. "Actually, the spell tells me you'd be really good at it."
"...Cool," you say, and turn to Hope. "What about you?"
"Well, I..." Hope starts.
"Don't trust me still, I understand," says Vivienne. "But since I know one of you can, I'll still make the offer to both of you. Would you like to become my apprentice, or apprentices?"
You don't feel any different, so you're not quite sure right away, and exchange another glance with Hope, who looks nervous.