Do you have any objective facts to support the opinion that Trump can win the nomination in a state where Democrat registrants outnumber Republicans by 2-1, and where the RCP average shows that Hillary would beat Trump by 20 points?
This business of politics is not precision engineering. You can't really produce "proof" that something will happen a certain way. Not even the polls get it correct much of the time.
I'm basing my prediction on the fact that i've kept tabs on the doings of Hillary since 1992, and know that once her opponents unloads on her with all the corruption and scandals that are inextricably linked to her, it will turn off the vast bulk of normal people.
Also, Trump has been a Democrat most of his life, and I see most New York Democrats as thinking he really still is, but is just running as a Republican because it gives him a better chance of winning.
I think most New Yorkers will look at the two, and conclude that Trump better represents their idea of what a President should look and behave like than does Obnoxious screeching scandal plagued Hillary.
Certainly Trump enjoys a much greater level of support from Blacks than have previous Republican candidates, and the estimates i've seen place him at around 25% of the Black vote. That alone will win him the election nationwide, and it will go along ways to winning the election just in New York.
I am a Cruz supporter, and I would rather have Cruz as the nominee, but my objective opinion is that if Trump gets the nomination, he will win the election in a massive landslide. Possibly the biggest ever landslide in US History.
I think Cruz would also win the nationwide election, but not by as much of a margin as would Trump.