Well north korea is a hermit country with little to lose.
China on the hand has alot more at stakes.
Most officials hide their wealth oversea. If their assets got frozen it would be devastating.
In Chinese culture i believe they said " take my life but dont take my wealth" meaning chinese guy can sacrifice himself but dont take his wealth because he wants to pass his wealth to his children.
Chinese officials may not care for wealth for himself but he like to give somethings to his children and wife.
Thats why alot of internal conflicts inside CCP currently.
This is what China born professor Yu Mao Chun explained to Trump admin regarding to internal thinkings of CCP members.
What Trump willing to do is hit and run. Like how he assasinated Solemani. He can ordered military to do some hit and run against China man made islands from a distance. If China respond too strong then its up to Congress whether to declare war on China.
Both countries have nuclear weapons.