"The United States and China do have a shared view that the North Korean nuclear programme is not acceptable and that the Korean Peninsula must not have nuclear weapons."
Common sense thinker:
"No they don't!"
China uses NK as a plausible denial "cut out" of their own weapons proliferation activities. To NK itself, also to the middle east. If China actually wanted NK not to have nukes, they'd stop sending them stuff used to make nukes. And if they were serious about getting the NK regime to change course on anything, they'd cease aid and trade while opening the border - and NK would collapse as a country inside of 6 months.