Trump has responded by calling his former aide a "lowlife".
Elsewhere in her book, she claims the president suffers from "mental decline" and alleges she once saw Trump chew up a piece of paper after a meeting with his then-lawyer Michael Cohen. "I rejected what other people said about him because they didn't know him like I did".
"It had finally sunk in that the person I'd thought I'd known so well for so long was actually a racist", she wrote, according to The Guardian. "Every critic, every detractor, will have to bow down to President Trump", Manigault Newman said in an interview with PBS in 2016.
But when pressed about her version in the book, Manigault Newman told to NPR: "I heard the tape". In the book, Manigault Newman says that Trump is a "racist" and claims that a tape exists of him using racial slurs from the set of "The Apprentice". Trump starred on the reality-TV show for years.More news: Tesla tweet 'highly problematic,' says former SEC boss
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The name-calling came in response to a question about a series of explosive claims in Manigault Newman's forthcoming book about her time in the Trump administration.
After she left the White House she says the president's allies tried to buy her silence, baiting her with a $15,000 a month job to serve in a "senior position" on Trump's 2020 re-election campaign.
Even when she turned it town she was bombarded with a "flurry" of letters from attorneys warning her to 'stay silent about Trump or else'.
As reports of accounts inside the book leaked out, White House Press Secretary Sarah Sanders slammed Manigault Newman as a "disgruntled former White House staffer" whose book is "riddled with lies and false accusations".