Moon, on his first overseas trip since taking office on May 10, said he hoped his visit would provide an opportunity to reaffirm the United States alliance and elevate economic ties "to the next level".
"It's the most important tool for the US President".
His nomination of Park Sang-ki, a legal scholar, came 11 days after his earlier candidate Ahn Kyong-whan withdrew after revelations he forged an ex-girlfriend's seal on a marriage licence application when he was young.
"With the North Korean security threat looming larger and larger, good chemistry between President Moon Jae-in and President Trump is essential", Thomas Byrne, president of The Korea Society in NY.
President Moon Jae-in, who only took office last month after a landslide election win, wants to engage with nuclear-armed Pyongyang.
During the briefing, White House officials emphasized that burden sharing will play a major role in talks with all other countries moving forward. "Without the cooperation of China in global sanctions done by the U.N. Security Council resolutions, these sanctions will not be effective at all", said Moon.
Colombian rebels have handed over almost all weapons
Courts: Those accused of crimes in the conflict will go before special courts and could get reduced sentences if they confess. Three women were killed at a shopping center in Bogota on June 17, in a bombing blamed on a fringe extremist group.
Moon also said reducing the joint military drills - seen as a threat by North Korea - could be considered only after irreversible and verifiable steps by Pyongyang to denuclearize.
"If North Korea breaks the agreement in the process and return to [develop] nuclear weapons, the North will be completely isolated in the worldwide community", Moon also told media on Wednesday.
"In that sense, its nuclear freeze will be the entrance and nuclear dismantlement the exit", he added. China has been lashing out at the US and South Korea for it. The method to kill Kim also included using biochemical and radioactive material when he appeared in public, said North Korean officials.
The deployment of the Terminal High Altitude Area Defense (THAAD) system has been a particularly sensitive issue.
North Korea has vowed to execute South Korea's former president and her spy director, accusing them of planning to assassinate its supreme leadership.
However, an article carried by South Korea' state news agency - quoting the country's foreign minister - confirms that its full-steam for the missile battery. And even then, "we must maintain and increase pressure in North Korea". Trump, on the other hand, has pushed for more sanctions from USA allies unilaterally and through the United Nations.