Look, facts change.
Trump HAS to respect how well Cruz has done.
If only Cruz had one iota of understanding how well Trump has done before 2015, and how meaningful and applicable that depth and breadth of experience is to the goal of saving the nation. His personal disrespect for Trump and ignorance of the scale of Trump's real-world accomplishment is galling.
I can't help but notice that the personal disrespect doesn't seem to bother Trump all that much; given the self-confidence that comes from having achieved a great deal, he appears to find it merely puzzling. But he does not like lying and misrepresentations and refutes these things, for which he gets called "thin-skinned", while we watched Dubya get flayed for 8 years and never say a word to clarify himself or correct the record.
Outright falshoods bother Trump. I was astonished at Cruz claiming that Trump wants to do away with the 2nd Amendment (180 degrees of wrongity-wrong) and Trump wants Obamacare (again, totally misunderstands and therefore misrepresents Trump's private sector, market-based solution, due to Cruz's not having any business experience himself).
There is the issue of downsizing government, which both agree needs to be done. But Trump is the only one who can also readily rebuild the private sector that has been cannibalized by the spread of government, because Trump is the one who has lived it before it became absolutely eviscerated and smothering; Cruz has not.