This is politics 101 - You never listen to what politicians say; you only what that they do (and what they have done).
And a very quick examination of NK reveals a leader who literally starves his whole nation to build his nuclear weapons. One that has assassinated close family and friends to remove the risk of political rivalry ... and made his country into a export center for the industrialized production of crystal meth and human trafficking.
So based on these very brief facts, when any problem that arrives in the near future, what could threaten his personal power, what will Kim Jong Un's natural reaction be?
I'll leave it to you to answer it ... but as you to reflect on the truism of Jeremiah 13:23
no-zombie