All of that can leave a theatergoer in a state of wariness — which, it turns out, is a great way to watch this play: trusting nothing, unsure where reality lies, guard firmly raised against any kind of charm. Mind you, “Jonah” will charm you anyway, and make you laugh. So will Jonah, the adorable day student (or is he?) whom Ana, our teenage heroine, meets at her boarding school (or does she?). Who and what is illusory here?