The Holland defender has joined Newcastle from Lille in a £35m deal.
"I don't and I actually don't want to think of that. This is how the world of football and the transfer market are developing," he told De Telegraaf, when asked about his price-tag. "I am still the down-to-earth kid from Badhoevedorp.
"It just shows how keen Newcastle United were to capture my signature. It has boosted my confidence and it's up to me now to repay that trust."
The centre-back admits that his newfound popularity with fans may take some time to get used to.
He said: "Straight after arrival, I noticed that everything in England is all about football. I may not be the best-known player but fans recognised me in the street and started a chat with me. And fans were waiting in the stadium and the training ground, where I was to undergo a medical.
"I must admit it will take some time to get used to that."