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"One, he's assertive. Two, he's not afraid to say exactly what's on his mind," Cuban said during a Fox News interview. "I think the American people are definitely interested in somebody that will tell them the truth."
In fact, the "Shark Tank" star has been such an outspoken fan of Trump's front-running primary campaign that some people have urged him to join Trump's hypothetical general-election ticket.
In July, Cuban told Business Insider that he would consider being Trump's vice president but probably wouldn't ultimately do it.
Fox's Neil Cavuto further pressed Cuban on the topic during their Tuesday interview.
"Is it just silly conjecture? Would you ever entertain it if he ever approached you and said, 'You know what? We'd make a great one-two billionaire team," Cavuto asked.
"Yeah, there's no way that he would ask me," Cuban replied. "And I just don't see it as a reality at all. He knows I couldn't ever be a second fiddle. So I don't think it could happen."
Throughout the summer, Cuban frequently weighed in on the presidential race - and Trump in particular - via his Cyber Dust social-media app.
He said there is one word to describe Trump: "killer." He praised Trump as the best thing to happen in politics in a long time. And he once told Business Insider that Mavericks fans love that Trump is shaking up the 2016 contest. (In turn, Trump included some of Cuban's praise on the back cover of his new campaign book, "Crippled America.")
Cuban further opined on the presidential race during his conversation with Cavuto. The outspoken investor said the ultimate victor would be the candidate who demonstrates two qualities.
"One: leadership. Can you show that you're a leader? Right, because if you may have run a state or you may have been a senator, that doesn't necessarily then mean you have leadership qualities," he said. "Two: the vision you have for the country. Can you support what you're saying?"
Cuban added: "I think Donald's got a chance to stand strong from a business perspective that the others just don't have."