 'Find the extra coffee-cup, and you can rest in peace.' Are you sure you don't know what it means? I asked him earnestly. 
He undeniably knows what all that nonsense about the extra coffee cup means.
mnli hypothesis: He undeniably knows what all that nonsense about the extra coffee cup means. premise:  'Find the extra coffee-cup, and you can rest in peace.' Are you sure you don't know what it means? I asked him earnestly. 