Trump rescinding the so-called "Iran deal" will improve his position with other nations, North Korea only being one of them. Actually, it wasn't a "deal" because Iran never signed anything.
Any "reputation" lost would be on Iran's side for entering into a "deal" that even they didn't commit to. Now the non-committal "deal" is off. Iran shouldn't have expected anything. Now, at the bargaining table, Trump will be in a better position because nations know that he will actually follow through and only make deals that are real and binding.
This goes back to Obama's great failure of his own base: He didn't make laws that would last, he only made policies that depend on him being president in order to last, in this he exploited his voters by giving them high hopes and letting them get angry—the whole time Obama never told his own supporters the truth that everything he accomplished after Obamacare was designed to be blown away with the wind.
Iranians weren't the only party with "gullible" written their foreheads; Obama voters were too, and Obama conned all of them.
The disturbing thing about the Iran "deal" is the reaction. Russia is very protective of that "deal". That should be enough to call the "deal" off—and to prove that there was no substance in the Russianewsgategate "collusion" myth. But, where are all the stories in the press about how the "deal" was bad for the US? Having given $1.7B in cash to Iran should at least receive mention from a supposed "non-biased" media.