His long-term future is yet to be decided, but Martinez is hoping he will choose to stay at Everton.
"What can we offer him?" Martinez asked reporters. "Just enjoying his football.
"He's a grounded and intelligent young man, who is not going to be swayed by the materialistic aspect of the game. As a player, happiness is something which is very important.
"When you can offer football happiness it is an incredible opportunity."
Lukaku himself has refused to be drawn on his future recently.