Zanoba negotiates aggressively, while Roxy complains [I don't want to be a court magician...]
The principal, taking advantage of Roxy's words, declared [Roxy belongs to the Magic University.]
An hour into negotiation, Zanoba finally budges.
He'll bring her with him, since she's involved this time, afterwards he'll return her to the University... that's the deal.
Put up unreasonable demands first, then coming back down.
That's the art of negotiation.