Arsenal and Sunderland are believed to be considering bids to take the Holland centre-half south next month but Norwegian Deila claimed the 23-year-old had told him he was content in Glasgow.
Van Dijk was signed for around ??2.6million??by Neil Lennon from FC Groningen on a four-year contract in June 2013.
Deila said: “He???s very happy. I have spoken with him and we are very happy to keep him as well. He???s a top player.
???For me, Virgil???s developing now and taking steps all the time which is very important. I am so happy to have him.??He is enjoying his football, playing well. That???s positive. He is such an important player for us.
???He has learned a lot from August. It???s not the first time a player has been affected. Others have been through these things as well. Stefan Johansen was the same.
???He came from the Euro Finals with Norway two years ago and played so badly for Stromsgodset. I had never seen him so bad because his mind was somewhere else.
???You can see a bit of that in John Guidetti now as well. If he can get his mind right, the goals will come again.??If you think too much about uncertainties, about what you???re going to earn, it takes energy out of what you???re going to do on the pitch.
???But Virgil learned from what happened in the summer and he knows that if he???s good enough things will happen. This is the way he wants to do it.???
Deila knows that the Dutchman is currently his prized Parkhead asset and added: ???He???s worth a lot of money but I am very calm. In my opinion he is a very good player now but he can be a world-class player.
???The next thing for him, even though he???s just 23, is to become a leader in defence who controls things.??He???s starting to do that but there are still a lot things to work on.???