Problem is, Trump says a lot of things that he doesn't mean. Or he forgets, it's a little unclear.
But the American intelligence community appears very interested in the guy and is known to have been working on extradition process in 2018.
If the American intelligence community wants to extradite Assange, I don't doubt somebody high-ranking in the CIA will sit down with the president and by the end of the meeting, have him thoroughly convinced that he's wanted Assange's extradition all along. They have agents trained in psychological operations and negotiation, and Trump is demonstrably an easy mark.
Funny. Trump has said he loves WikiLeaks, and likely has no interest in Assange getting extradited to the US.