She also insists that she heard Trump using epithets about George Conway, White House counselor Kellyanne Conway's husband.
White House Press Secretary Sarah Huckabee Sanders released an official statement on Friday, calling Manigault-Newman a "disgruntled former White House employee".
Manigault Newman also suggested she now believed that she was pushed out of the White House because she was close to getting hold of the secret tapes revealing Trump using the racist word.
Omarosa also says there are tapes that exist in which Trump used the n-word on the set of the TV show, "Celebrity Apprentice".
Michael Wolff's "Fire and Fury: Inside the Trump White House" rocked the West Wing when it hit shelves in January and caused Trump's inner circle to sever ties with Steve Bannon, his former chief strategist. She served as director of communications for the White House office of public liaison before her dismissal last December. According to The Guardian, Manigault-Newman confirmed the 2016 rumors alleging there are tapes of "The Apprentice" outtakes in which Trump could be heard saying "n****r".
The claims, based on hearsay, are among the more explosive that Manigault Newman makes in the book, Unhinged. But she admits she has not heard it. They all told me that President Trump hadn't just dropped a single n-word bomb.
Concerning the president, Manigault-Newman wrote about a "growing realization that Donald Trump was indeed a racist, a bigot and a misogynist". Tom Arnold, a former contestant on the show who was once married to disgraced star Roseanne Barr, said he has Trump tapes too. "F***ing FLIP! Disloyal! F***ing Goo-goo". George Conway, a lawyer, is a vocal critic of the Trump administration on Twitter and in articles he has written for Lawfare.
"This is why people don't trust these 'exposés, ' which is especially bad for authors who actually are good and reliable", he concluded, referring to Manigault's book.
After she was sacked, Manigault Newman wrote, she received a call from Trump campaign adviser Lara Trump, the president's daughter-in-law, offering her a job and the monthly contract in exchange for her silence.
'Using the N-word was not just the way he talks but, more disturbing, it was how he thought of me and African-Americans as a whole, ' Omarosa wrote in 'Unhinged'.
Later, a source from The Apprentice contacted her, claiming to be in possession of the tape.
Even as aides warned him against it, Trump often spoke to Manigault Newman and invited her to come by the Oval Office, a practice that Kelly eventually curtailed.