Sitting down for an interview with PEOPLE in his office at Trump Tower, Donald Trump is charming, candid (he answered any question posed to him) – and very confident.
"When you see you're number one in every poll that makes any criticism go away very quickly," he says. "If I'm able to get the nomination, my polling looks very good against Hillary or whoever it may be. I think I'll win."
Financially, he's prepared for the enormous cost of running a campaign (Obama's cost an estimated $1 billion in 2012).
What has been slightly more difficult to reconcile is the impact the campaign has had on his family life. At 69 he's a father of five (Donald Jr., 37, Ivanka, 33, and Eric, 31, with his ex wife Ivana; Tiffany, 21, with ex wife Marla Maples; and Barron, 9, with wife Melania) and grandfather to seven (daughter Ivanka's current pregnancy will make it eight).
"I just don't have the time that I would love to spend with my children and my wife," he says. "I see less of my grandchildren than I might like. But they get how important this is."
This is Melania's first major interview, conducted in the family's lavish 66th floor penthouse, and she says she's there to support her husband's efforts.
"My husband is traveling all the time," she says. "Barron needs somebody as a parent, so I am with him all the time."
Reflecting on her husband's often outrageous comments, Melania says she's "not ready to get political yet," but stands by him.
"He is who he is," she says. "Even if you give him advice, he will maybe take it in, but then he will do it the way he wants to do it. You cannot change a person. Let them be. Let them be the way they are."
So far, that strategy seems to be working.
"He's clear," his daughter Tiffany says, defending her father's more controversial remarks. (He dealt with huge fallout in June, after making inflammatory comments on illegal immigrants, and inspired a backlash last month after he commented on fellow nominee Carly Fiorina's appearance.)
"It's nice not to have to overanalyze someone's speech to see what the meaning really is," she adds.
Looking ahead to a potential future in the White House, "It's a little scary for Barron," Trump concedes. "He thinks he is going to be taken away from friends. But I tell him if this happens, Daddy will help people, and can help children like him, and that makes him happy."
For her part, Melania says she's cautiously optimistic.
"It's a long road. I take it day by day," she says. "My husband has a lot of people cheering for him. We will see."
But for now, the couple says they're trying to enjoy what may be their last moments of relative privacy.
"My life is so busy and so crazy, and I'm away all the time," says Trump. "If I can just stay home and do nothing, it's considered a great luxury."
For much more of our exclusive interview – and at-home photos! – with the Trumps, pick up a copy of the new issue of PEOPLE, on newsstands Friday