It may have been a relatively hastily-arranged meeting. But it was probably more productive than the two leaders' well-prepared rendezvous in Hanoi, Vietnam, four months ago.

In briefly crossing the military demarcation line in the truce town of Panmunjom on Sunday, Donald Trump boldly went where no sitting US president has gone before, stepping into both the Democratic People's Republic of Korea and history.

What was seemingly planned as a two-minute meet-and-greet with DPRK top leader Kim Jong-un, became something more substantial as the affinity between the two, turned into a meet-the-family moment. Apparently impromptu, after taking 20 steps into the DPRK with Kim at his side, Trump escorted the DPRK leader into the Republic of Korea for 50 minutes of private talks in what is known as the Freedom House where they were joined by his daughter Ivanka Trump and son-in-law Jared Kushner, both senior White House advisors.

Which perhaps gives some substance to previous suggestions that his approach toward the Korean Peninsula is not full-heartedly supported by his more hawkish secretary of state and his national security advisor who reportedly favor a more hard-line approach.

Tellingly, after his talks with Kim, Trump hinted at a more flexible approach, saying that although the sanctions imposed on the DPRK will remain in place for the time being, at some point in the negotiations "things can happen", suggesting a step-by-step roadmap to the DPRK's denuclearization.

While Trump will no doubt take the plaudits, it is unlikely the third face-to-face meeting would have happened without the involvement of President Xi Jinping, who met with both Kim and Trump in the space of a week, which is believed to have set the stage for their get-together, or that of Republic of Korea President Moon Jae-in who facilitated Sunday's meeting. Both Xi and Moon have repeatedly shown their dedication to keeping Washington and Pyongyang talking.

Hopefully, the third Trump-Kim meeting in less than a year has further deepened mutual trust and understanding, not only between the two leaders, but also between the two nations.

If the evident goodwill and shared willingness to be friends on the personal level can be extended to the national level and materialized into actions, it would undoubtedly create a new window of opportunity to achieve real progress in the peninsula issue.

Yet, given the complexity of the issue, and the long estrangement between Washington and Pyongyang, there is still a long way ahead to achieve denuclearization and lasting peace on the peninsula.