"I know they are in talks together about a new contract but, if it is 99 per cent, I need to believe his agent," the Dutchman said. "It's a big deal and that is what the club is showing to keep the best players and do everything to keep them in the club because that is the future.
"Of course you don't know in football what can happen in one year but at least there is understanding and the boy likes to stay and he is a big part of the Everton future.
"They [players] sign new contracts but don't say they will stay until the end of the contract. That's football, that's business, we will see. But I think first if the new deal is done then that's good news."