https://www.thesun.co.uk/news/6154655/north-south-korea-agree-denuclearisation-kim-jong-un-moon-jae-in/
Yeah I don't think the North Koreans have declared this. This is something the South is pushing.
Even still, I am pretty sure Kim has gotten the message how big of a deal this is to the US and to Trump, as Trump has said, if there is a war with North Korea, it will be fought over there and not here.
And, I am sure everyone has seen Trump has bombed Syria TWICE while Syria is under the protection of Russia. So I think Kim has probably figured out he has to change his game a bit.
But after reading up on North Korean negotiating tactics the last 6 decades, and you should too, I think you'll find that the North Koreans are masters as getting something while not giving up anything.
And lets also note that with all the pleasantries and handshakes, Kim had his own brother assassinated. So lets not give Kim too much credit yet.
The real test is if Kim promises Trump to give up the nukes when they meet, and work out a definitive plan to make that happen.