Mauricio Pochettino’s side is currently out of the Champions League places, although they can draw level on points with fourth-placed Liverpool if they win at Wembley and overtake Jurgen Klopp’s side if they beat the Toffees by five goals or more.
But the club has a new 61 500-seat stadium to pay for at a time when rivals with deeper pockets are eyeing some of their top performers.
Top scorer Kane is reportedly coveted by Real Madrid and the Champions League holders have also been linked with midfielder Alli, along with Paris Saint-Germain. Left-back Danny Rose is believed to be a target for Manchester United.
But Levy has made it clear that the current window is a time for squad-strengthening, not weakening, and said he would reject any unwanted offers in the summer as well.
“I’m 100 percent confident,” he said. “Every single player that we want to keep, I can assure you will be playing for Tottenham Hotspur next season.
“Mauricio’s strategy has always been that if an opportunity arises that he thinks can improve the squad then we will need to look at it, but January is always a very difficult window.”
Levy is in negotiations with Alli over a new contract that would bring him roughly into line with the money paid to Kane, who is Tottenham’s highest earner and who may be granted a contract upgrade himself soon.