Right.
Negotiating with Trump is like negotiating with Hamas.
You can't trust what he says, and he is likely to break whatever deal he has agreed to, according to how he feels in any particular moment.
Also, back to Hamas/Israel (sorry for using that as an example in this thread), what happened to Trump's "hell to pay" threat if Hamas didn't return all the hostages two Saturdays ago, or whenever his stated deadline was?
At some point, either you back up your threats with concrete action, or the threats become something your adversary will not take seriously.
Everybody knows Trump's playbook is his "art of the deal", where he threatens something extreme, and then settles for something less extreme that the other side may not like, but will tolerate.
The only trouble with that is, in time, your adversaries will figure out your modus operandi, and that negotiating technique will stop working altogether.