In his acceptance speech, the 58-year-old senator from the battleground state of Virginia, mocked the 70-year-old reality TV star's often cited remarks "believe me", amid applause from the audience.
"The guy promises a lot. But you might have noticed, he has a habit of saying the same two words right after he makes his biggest promises. You guys know the words I mean? 'Believe me. It's gonna be great - believe me!'" Kaine said.
"Do you really believe him? Donald Trump's whole career says you better not," he added.
Kaine, who has been a strong advocate of India US relationship, said it is Democratic presidential nominee Hillary Clinton who is ready to take over as the next US president.
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"Now Hillary is ready. Ready to fight, ready to win, ready to lead," Kaine said amid cheers and applause from thousands of party delegates, leaders and supporters.
"Any party that would nominate Donald Trump for president has moved too far away from his party of Lincoln.
"And I'll tell you, if any of you are looking for that party of Lincoln, we have got a home for you right here in the Democratic Party," he said amid applause.
Trump has a passion, "it's himself", Kaine said.
"With Hillary, it is not just words, it's accomplishments. She delivers. As senator, after 9/11 I got my New Yorkers right here and my Virginians right here. She battled -- she battled congressional Republicans to care for the first responders who went in to the Towers, who went in to the Pentagon and saved the victims of those terrorist attacks.
"She was not afraid to stand up against thugs and dictators, and as a key part of the Obama national security team, they decided to go to the ends of the earth to wipe out (al-Qaeda chief) Osama bin Laden," he said.