According to Russia, it’s “absolutely mandatory” that which country “never, never, ever” becomes a NATO member?

After hours of negotiations between the US Deputy Secretary of State and Russia’s Deputy Foreign Minister in Geneva on Jan. 10, 2022, Russia’s lead negotiator insisted that it was “absolutely mandatory” that Ukraine “never, never, ever” becomes a NATO member. His American counterpart argued that the US “will not allow anyone to slam closed NATO’s open-door policy.” As of January 2022, Russia has about 100,000 troops on the Ukraine border.