Well, Brahne is either not impressed if you make 1 or more mistakes, or quite impressed if you made none, no other variant. But you only get the Moonstone and 10 000 gil if you impress all 100 of the audience. And then she tells Steiner that "the performance today is quite extraodinary. Here, I feel like giving you this" Otherwise she's just "Take this and go find Garnet". So we can say that she really is impressed when you do it 100% perfect

Selena