The Wall Street Journal first reported the direct confirmation by the North.
There is still no guarantee that the talks will happen, or that Mr. Kim is prepared to discuss denuclearization of the sort that the United States government envisions, which would entail entirely giving up the very weapons that the North has seen as crucial to its continued existence. It is also unclear what kind of concessions the United States would be willing to make to secure commitments from Pyongyang.
But the direct communication between the two countries about Mr. Kim’s intentions appeared to signal that both sides were working to plant the seeds for negotiations.
The efforts to arrange talks between Mr. Trump and Mr. Kim have posed steep challenges for the administration, whose North Korea policy is centered on the imposition of crippling sanctions, backed by the threat of military action — what the administration calls its “maximum pressure campaign.”
Before the president abruptly agreed to a summit meeting last month — a gesture that followed a sudden shift of his own by Mr. Kim toward talk of peace — the administration had done little planning for how a diplomatic negotiation would unfold, according to people briefed on the process.
The preparations are also taking place as Mr. Trump has lost or opted not to hire seasoned diplomats experienced in dealing with the North. The State Department’s chief North Korea negotiator, Joseph Y. Yun, recently announced his departure from the Foreign Service. And the White House decided against nominating Victor Cha, another experienced negotiator, as ambassador to Seoul.
Word of Mr. Kim’s willingness to talk about denuclearization came the day before John R. Bolton, who has made the legal case for a pre-emptive attack on North Korea, was to officially begin work as Mr. Trump’s new national security adviser.