SINGAPORE — A sense of "realistic optimism" is in the air ahead of the highly anticipated meeting on Tuesday between United States president Donald Trump and North Korean leader Kim Jong-un, Singapore's Foreign Affairs Minister Vivian Balakrishnan said.

With all eyes on the occasion, he also said that everyone just has to "wait and see" and temper their expectations to avoid "wishful optimism".

Having met both leaders personally, Dr Balakrishnan told British broadcaster BBC in an interview on Monday (June 11) that it is "very clear" both leaders want something significant out of this summit "at an emotional level".

The summit, which will be the first face-to-face meeting between a sitting US president and a North Korean leader, will be held at Sentosa Island's Capella hotel.

Dr Balakrishnan, who just returned from working visits to Washington, US and Pyongyang, North Korea, is not expecting this first meeting to completely iron out decades of conflict and it is only the first step of a "much longer and difficult process".

"(What) I would say is that both of them have indicated quite clearly that this is the first meeting, that you don't resolve 70 years of suspicion, of war, and quite frankly, of previous diplomatic failures, in one meeting. So I think both of them are also signalling to all of us to manage our expectations. It's a huge step. It's a positive step. It's not the final step."

On the agenda are the denuclearisation of the Korean peninsula, peace talks, and other issues of mutual concern.

"Let's see what agreements, or at least, tentative agreements they can come up with on Tuesday or latest, Wednesday," the foreign affairs minister said. "If you see a de-escalation of tension, which, hopefully, in turn would be accompanied by security guarantees on both sides, lowering the possibility of war and enhancing the prospects for economic development — all those would be signs of success."

The historic meeting will be an opportunity for both countries to start building a "reservoir of trust", Dr Balakrishnan noted, referring to longstanding tensions between both sides as a "hangover" of the Cold War.

"The most important missing ingredient in all these seven decades is the lack of strategic trust," he said.

Mr Kim has made promises of denuclearisation before. Over the past three years, Pyongyang has talked about freezing its pursuit of nuclear weapons, but those pledges never quelled its nuclear ambition.

Both he and Mr Trump have also traded insults and threats over Pyongyang's nuclear missile programme.

Asked by BBC's Asia business correspondent Karishma Vaswani if the North Korean leader can be trusted, Dr Balakrishnan said that he senses in Mr Kim "a real desire for change", as seen partly by his willingness to come to the negotiating table with Mr Trump.

"He said that he now wants to focus on economic development… he feels that he has achieved his military objectives."

Mr Trump has also been willing to "break the taboos and boundaries of the past", he added.

These two "completely unconventional leaders" may be able to "pull rabbits out of a hat that the rest of us conventional diplomats would not have been able to do", Dr Balakrishnan mused.

On how Singapore expects to move forward in economic partnership with North Korea, a country that has "this attitude of being quite hostile" in the past, he said: "You must not look for instant solutions… It starts with sincerity and goodwill. Next, you build up your reservoir of trust, strategic trust, and then step by step, you establish a track record of win-win outcomes, project by project, deal by deal."

He believes that Singapore's advantage in building diplomatic ties is that it is just a tiny city-state. "People know us, they know our style, they know that we are honest, we are reliable, we are transparent, we are friends with everyone and we don't play games, and we maintain a consistent, principled approach. That actually puts us in good stead, in a very uncertain, somewhat volatile world."

Based on his short visit to Pyongyang and interaction with the North Korean delegation, Dr Balakrishnan said that "there is no reason to assume that (North Korea) cannot achieve that level of development that the rest of us, in South-east Asia, have had".

However, this may not necessarily be a "China-led model" in terms of economic development, as suggested by the BBC interviewer.

"The North Koreans, or ultimately the Korean people, will have to decide on their model. We should leave it at that, we should give them the space, the opportunity, the security to make those choices."

Stressing that there is no "single monolithic model" that serves as a formula to development, he said: "Every political system has to evolve to fit its own unique national circumstances.

"What people all over the world want, and especially in Asia — we want good jobs, we want peace and security, and we want hope for a better future for our children and our grandchildren. So these are universal hopes, but the recipes are different in each and every nation."