“He doesn't think Trump will be the nominee” is an attack?
On what planet is that?
Every single candidate in any election thinks they will win it instead of their opponent. Why would anyone run with the intention of losing?
That was the first hint of any negative comment between Trump and Cruz. It was a pointless remark, except to be used by Cruz to end the truce with Trump and begin the barbs between the two.
Trump's only response was to say: "He has to say that." But it was used by Cruz to end the truce and begin his attempts to advance himself by criticizing Trump.
Cruz is the vote splitter the GOPe has been praying for, and he is about the only hope they have of preventing Trump from going to the convention with a majority of delegates.