(CNN) North Korean leader Kim Jong Un has "unwavering trust for President Trump" and wants to achieve the denuclearization of the Korean Peninsula before the US leader finishes his term, South Korean officials said Thursday.

"This trust, despite some difficulties surfaced during the negotiation process between the US and the North, will continue," said South Korean special envoy Chung Eun-yong, who met with Kim in Pyongyang on Wednesday.

Chung said Kim told him North Korea "was willing to take more active measures toward denuclearization if his advance steps could be met with matching measures (from the US)."

Kim said he had "never said anything bad about President Trump to anyone," Chung reported, adding that the North Korean leader expressed a wish to end 70 years of hostilities on the Korean Peninsula.

Chung had just returned from a trip north to finalize plans for a meeting between Kim and South Korean President Moon Jae-In, to be held in Pyongyang from September 18 to 20. It will be the first trip by a sitting South Korean president to the North Korean capital since 2007, and the third meeting between the two men this year.

This picture from North Korea's official Korean Central News Agency (KCNA) taken on September 5, 2018 shows North Korean leader Kim Jong Un (R) meeting with South Korean president's special envoy Chung Eui-yong (L) in Pyongyang.

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