I think if Trump were running, he'd be running already. Why wait? But he doesn't want to say he's not running and see the fundraising cash dry up.
I suspect he genuinely doesn’t know if he’s running. But I get the impression he feels like he’s had enough of Washington and I’m sure Melania has.
From what I understand, if Trump were to announce now, he would be subject to stringent campaign finance laws and could not raise as much money.