It's not the end you should be worrying about, it's the means.
Trump has made several big promises. I don’t think his ego will allow him to break them. He’s someone who love to see his poll numbers increase. Breaking a promise achieve the opposite of this. To what end? Why would he break them. He gain nothing from breaking his promise. He’s not governed/influenced by donors, special interest, lobbyists. What drives him is his desire to be regarded as the best president ever, better than Reagan