Imagine what would happen if "the presumptive Republican nominee" for president happened to select one of the smartest and most energetic people in Congress today as his vice-presidential running mate. Heads would explode.
Ludmya Bourdeau "Mia" Love (born December 6, 1975) is an American politician and the U.S. Representative from Utah's 4th congressional district. She is the first Haitian American and the first black female Republican in Congress, as well as the first African American to be elected to Congress from Utah. -Wiki biography
Democratics always attack Republicans as evil, hate-filled bigots, and some of Trump's rhetoric to date has simply opened the door further to such attacks. Imagine, then, the implosion that would necessarily follow if he got Mia to run with him. Just the bumper-stickers would make Democrat heads explode. How do they fight Trump/Love?
Americans in general have had just about enough of the establishment in both parties. Pantsuit's as establishment as you can get, and coupled with her known inability to tell the truth about anything, she's not well-liked. Trump's not an establishment guy, but there are many reasons not to like him either.
But a Trump/Love ticket could very well galvanize voters across party lines, including Independents. They might not be willing to vote for him alone, but with a smart black woman like Mia on the ticket, they might well vote for her (while secretly hoping that The Donald suffers a massive coronary infarction).