"I just received a beautiful letter from Kim Jong Un, and I think the relationship is very well," Trump told reporters at the White House. "It was a very personal, very warm, very nice letter."
Trump noted that the third summit with the North Korean leader could take place soon.
Trump also said that he was aware of the media report claiming that Kim's slain half-brother was a CIA source.
Kim Jong-nam was killed at Kuala Lumpur International Airport in February of 2017. The Wall Street Journal reported on Monday that he had travelled to Malaysia to meet his CIA contact, although that may not have been the sole purpose of the trip.