She is only allowed to fly to her destination, not anywhere else. She notices that she is not where she should be, that she cannot progress to where she was told to go, and she careens out of control when her wings won't flap anymore, and she crashes.
"I'm curious about how it works and what sorts of things it can do. What I've specifically been asked to verify is that it can do things that would be hard to accomplish without magic, but that can be difficult to verify. I don't think I've heard of anyone being able to grow a tree that quickly, but it wouldn't astonish me if someone could. I'm told you can heal injuries much more effectively than a mundane doctor or medtech, but I don't have any injured people on hand to test that with."
"Silver saw me fix my broken hand and black eye... I'm not really keen on replicating either." Pause. "I can move my tree around." The tree waves its branches more energetically and irrespective of wind than trees are normally wont to do.
"I wouldn't ask you to injure yourself just to prove a point. But... hm. What sorts of things can you heal? If someone had a very old injury that mostly didn't trouble them anymore, could you heal it without knowing what it was?"
"I'd certainly accept that as strong evidence of magic, and I happen to have an injury like that."
"I'll need to be around you for a bit longer before I can cast anything on you. Maybe another ten minutes."
"That and the healing would be a comprehensive demonstration that you have magic of the described kinds, I think."
Promise flies back over to her tree, makes it give her a few more little fenceposts, and resumes placing them, looking at Copper periodically.
"Well, you've repaired nerve damage that some of the best surgeons in the galaxy couldn't fix. I think I'm satisfied you're magical."
"I'll get out of your hair. If you tire of Silver's company and want someone else to talk to, he can summon me anytime and I'll be visiting now and then to see how you're doing."
Promise draws and writes and thinks. She sings and sews and grows crops. She sleeps and eats and drinks.
Gold is content to let Silver and Copper handle all Promise-related things; Eleven is, at least for now, content to let the Emperor decide what is to be done about Promise, and the Emperor's decision is that Promise should be allowed to remain comfortably in her tree at the Electrically Conductive Metals family's lake house until such time as she would like to talk to Silver about building some gates.
Promise takes about two weeks remaining comfortably in her tree at the Electrically Conductive Metals family's lake house before she remarks that she is getting a little bored.