Hillary could well do this.
On the other hand, Trump could get 53% of the vote against her if things went well.
Trump will prove to be a boom-or-bust for the GOP. His upside, IMO, is greater than any other candidate, including Kasich.
What upside is there to a man who called Mexican illegal immigrants rapists and drug dealers? All he will do is drive up Hispanic turnout to the point where states that should be in play for a Republican become out of reach.
They'd have been better off nominating pretty much anyone else. Even Jim Gilmore.