I have no idea why other folks vote for Trump. In all appearances, the theme to the large voter turn out for Trump seems to be that they are fed up with the current administration, and Hillary has promised to stay on his course. Trump is promising a real change from the current failed policies.

Now, as far as I am concerned I did not vote for him in the primary. I voted against him. BUT, if he gets the nomination he will get my vote in the primary. Why? Because I find it extremely important that neither Hillary or Sanders gets elected. I would vote for any of the original 17 candidates if it meant keeping Hillary or Sanders from winning. This country is hurting enough as it is. More of the same will do it more damage. So, if Trump gets the nomination he gets my vote. If Cruz gets the nomination, he gets my vote.
As bad as both are, they are so much better than a Socialist or a criminal that has no respect for national security, hates the military and cheats on her taxes.