North Korean leader Kim Jong-un and U.S. President Donald Trump sign a joint statement following their talks at the Capella Hotel on Sentosa in Singapore, Tuesday. / Reuters-Yonhap

By Yi Whan-woo

North Korean leader Kim Jong-un's summit with U.S. President Donald Trump in Singapore, Tuesday, apparently helped him change his reputation from a "madman" to a "normal leader," analysts says.

The agreement the two leaders signed also benefited Kim in his efforts to transform his image from a "rocket man" into a global leader who strives for peace and denuclearization.

Trump had called Kim a "madman" and "rocket man" in a derogatory manner for carrying out a series of nuclear and ballistic missiles tests, assassinating his elder half-brother Kim Jong-nam, executing his aides for petty reasons, starving his people to death and torturing and killing political prisoners.

But Trump was courteous and respectful toward Kim as they shook hands during live coverage at the Capella Hotel before the summit.

The leaders also had a three-course meal at their working lunch and walked side-by-side as they went for a stroll afterwards.

The occasion was unthinkable only months ago and it apparently gave the impression that Trump was treating Kim as equally as he does other heads of states, according to Park Won-gon, an international relations professor at Handong Global University.

"Kim has wanted to be become a normal leader and the summit will definitely boost him in achieving such a goal," Park said.

The professor also referred to the "special bond" that Trump mentioned referring to his relationship with Kim.

The U.S. president said he would meet the North Korean leader many times and that he would be "absolutely" willing to invite Kim to the White House.

In their joint statement released after the summit, Trump promised a "security guarantee" to North Korea, which Kim has strongly demanded in his plan to shift away from the country's nuclear program to focus on rebuilding the economy.

Michael Kovrig, senior adviser at the Crisp Group, a Belgium-based non-profit organization aimed at preventing war, said the summit was a "huge win" for Kim, adding that Kim had the "the prestige and propaganda coup of meeting one-on-one with the (U.S.) President, while armed with a nuclear deterrent."

Several diplomatic sources echoed a similar view, claiming warm words and positive optics seemed to be a long way from when Trump was threatening to rain down "fire and fury" on Pyongyang and Kim attacked Trump as a "mentally deranged U.S. dotard."

The agreement with Trump is likely to pave the way for Kim to open dialogue with other world leaders, including Japanese Prime Minister Shinzo Abe and Russian President Vladimir Putin, according to the sources.

Kim has only met the leaders of South Korea, China and the U.S., all this year, after taking power in December 2011.

The sources speculated that the Trump-Kim deal would especially benefit North Korea in opening talks with U.S. allies.

Kim reaffirmed "unwavering commitment to complete denuclearization of the Korean Peninsula."

"This may serve as a ticket to establishing diplomatic relations with the Western countries," a source said.

But some critics remained cautious about Kim becoming a "normal leader."

They pointed out that complete, verifiable and irreversible dismantlement (CVID) of North Korea's nuclear weapons was not mentioned in the joint statement.

CVID is seen a critical element to prevent North Korea from going back to its nuclear program and to achieve a normal Korea.