VP slot. Period. He will agree to release his delegates and endorse Trump for being named Trump's running mate.
Trump would prefer to hit 1,237 on his own without a deal, but if he can't, do you think he will turn down a chance to win by with 1800+ delegates on the first ballot in exchange for giving the VP slot to Cruz?
Trump wants to win, and that would put him in as the nominee by an overwhelming vote.
Read "The Art of the Deal" if you don't think Trump will make that deal.
Trump just jumped up 2600 or so @ 99%.
Trump won
If you think Trump would pick Cruz as VP you need serious mental help.
Kasich and would be a better choice.
We need OH and Kasich will likely have enough delegates, plus Kasich will likely bring some unpledged delegates along for the ride.