In an almost surreal moment, North Korean dictator Kim Jong-un crossed over the demarcation line separating the two Koreas and proceeded to shake hands and embrace South Korean President Moon Jae-in. The two leaders then proceeded to a meeting, after which both declared their commitment to moving forward in achieving “a nuclear-free Korean Peninsula through complete denuclearization” and an end to the decades-long Korean War. The event culminated in the planting of a pine tree meant to symbolize a growing peace. It is a stunning about-face from one year ago when Kim was threatening both South Korea and the U.S. with nuclear annihilation.

The goodwill meeting between the two bitter foes is clearly designed to lay the ground work for a highly anticipated summit between Kim and President Donald Trump, which may come as early as May. Trump has offered cautious optimism for progress on denuclearization and even praised Kim, stating, “Kim Jong-un … really has been very open. I think very honorable, from everything we’re seeing.”

The meeting largely steered clear of any specifics on denuclearization, though Kim earlier this week agreed to end nuclear tests and missile launches — actions that directly brought Trump’s and the world’s ire. And clearly the meeting with Trump will be the one dealing with the specifics on denuclearization.

Cautious optimism is probably the best stance to take here. The world has witnessed similar diplomatic efforts in the past only to see North Korea take advantage of sanctions relief while continuing to develop nuclear weapons. The question is whether the results will be any different this time. Trump seems committed to ensuring that the only acceptable outcome is denuclearization, and it may be that Kim is willing to offer that sizable bargaining chip in order to ensure both sanctions relief and his stranglehold on power. It also appears that China has tired of Kim’s provocations, which only invite world condemnation and serve as an economic lead weight in the region. Whatever Kim’s underlying motivation, there is no question Trump is seeing diplomatic progress no one thought possible just months ago.