The veteran Belgium midfielder was speaking after scoring in their 6-0 win against Liechtenstein last night.
He said, "I'm settling in well in Naples after a tough summer of intense work. I gave it my all and I feel in great shape. I still have a few things to sort out, like the move, but everything's fine.
"In southern Italy, everyone supports Napoli, which is fantastic. Napoli is a great team that can still grow a lot. I hope something good can come of it."
Belgium coach Rudi Garcia decided in recent weeks to remove De Bruyne's captaincy and give it to Youri Tielemans, but the Manchester City legend shrugged it off.
"Garcia spoke to me and (Romelu) Lukaku earlier this week and explained it to us. The coach has made a decision that could last several years. It's a long-term choice, for consistency."