Kim got Trump to agree & publicly state "it is important to abide by the principle of step-by-step and simultaneous action in achieving peace, stability and denuclearization of the Korean Peninsula.". That goes directly against what Trump administration has said so far.
Last month, Secretary of State Mike Pompeo
told the House Foreign Affairs Committee that "the model that we have laid forth is a rapid denuclearization, total and complete, that won't be extended over time." The administration's argument is that the incremental approach used by past administrations has allowed North Korea to extract rewards and incentives from the U.S., only to ultimately renege and refuse to give up its nukes.
Trump gave Kim what he always wanted. Trump rewarded Korea's nuclear achievements by giving Kim Formal World status as "Korea's Head of State" Kim is using that nuclear power to negotiate with the US & World for Korea!
Trump offered North Korea unspecified security guarantees, Trump also "guarantees that it does not seek to overthrow the current regime in North Korea." So now the USA has to protect North korea & it's Supreme Leader Kim.
He also suggested that the United Nations should consider easing sanctions on Pyongyang to reward it for progress towards giving up its nuclear program. "Sanctions are not an end in themselves," he said, "the Security Council, through its actions, should support the current diplomatic negotiations."
China's Shi Yinhong said Trump's pledge to halt military maneuvers is, from China's perspective, almost "too good to be true." Shi predicts that such a move could face stiff domestic opposition. If U.S. troops in South Korea were to really halt military exercises, he says, it could cause allies to lose confidence in Washington and undermine the entire U.S. military presence in Asia. Trump won't get China's military off those islands in South China Sea or from controlling & taking back Hong Kong.