The centre-back, 27, has been linked with a move to Old Trafford in recent transfer windows.
Koulibaly did not put Napoli supporters' fears at ease when quizzed on a potential transfer.
He said: "The future? I am a Napoli player and I will give one hundred percent to win something with this shirt.
"The market is full of talk. I prefer facts, which then help us win and become great together."