Against a background of continued USA leaks threatening a 'surgical strike' on the DPRK (North Korea), a move that does not have complete support in the South, the North invoked 'charm' as it's next 'weapon.'
Here's how the Republic of Korea's (South Korea), government owned News Agency (Arirang News) saw the North's charm offensive:
https://www.youtube.com/watch?v=lIf_mkr-ovY
And the Hongkong based South China Morning Post's view:
https://www.youtube.com/watch?v=TwxO5skDbzY
Why the sudden change in Kim Jong-un's methodology?
My interpretation is that now the North has the world's attention with the view that the North has a nuclear capability, they likely feel they can relax the tension. That view is based on the oft discussed view (by Korea watchers) that the North's worst fear was some sort of 'regime-change effort by the USA. Feeling safer behind their nuclear wall, they used the winter Olympics to influence public opinion in South Korea. Time will tell whether this is the way it will work out.
Of course, it may be that the sanctions are hurting more than may be apparent. But, even though China has, from all reports, severely cut official trade across border with NK, there are almost no reports that Russia has cut its trade with NK. A train line from Russia to NK is apparently working normally, and of course Vladivostok, Russia's major centre in East Siberia, is less than 500 km away.
Will it last?
Maybe! Kim Jong-un's sister hand delivered an invitation to the South's President Moon to visit North Korea for talks.
Arirang News speculates on that topic: