Please define "failure"?
If, despite signed agreements, Kim is found to have tested/sold hi-grade uranium to a 3rd party? Would that be President Trump's fault?
LOL! @Wingnut nailed it above. That would be Ms. Albright and Bubba.
And that's the only scenario I can see.
Perhaps, Kim was told by China to open up to a little <cough>.......Capialism?
You're waffling, DC. You introduced a third option so that it could clearly not be Trump's fault.
I give him much credit for this, and hope he succeeds. But, if he doesn't, then yes, it is on him.