In the book, Manigault Newman, who was a contestant on Trump's "The Apprentice" reality show and later served as a senior adviser to the president, hurls a litany of allegations, painting the president as scattered, self-absorbed, misogynistic and insecure.
She alleges that, during the making of U.S. version of The Apprentice, which Trump fronted for several years, the future president muttered the racial slur "multiple times".
Trump, she said she'd concluded after years of defending him, was a bigot.
However she claims that Mr Kelly was aware that she was close to getting her hands on Mr Trump's compromising Apprentice tapes which prompted him to fire her under another pretext.
She claims she also personally witnessed Trump using racial epithets when referencing his aide Kellyanne Conway's husband George, who is half-Filipino. From claiming she was contacted by the Federal Bureau of Investigation to claims that she was offered hush money payments, this book is full of bombshell claims. Trump has continuously insisted that he is not a "racist", but if audio recordings do eventually come about showing that he did use the n-word to criticize African Americans, it would be hard for him to deny that label any longer.
At the time, an early Apprentice producer took to Twitter to say "there are far worse" behind-the-scenes tapes from the show.
Britain welcomes United States sanctions on Russian Federation over Salisbury nerve agent attack
Skripal and his daughter were poisoned by the Novichok military-grade nerve agent in the English city of Salisbury in March. He said the new sanctions amount to "inflicting a punishment in the absence of a crime, in the tradition of lynch law".
In her new memoir, "Unhinged", she writes sources told her the tape was from outtakes of his NBC series. She is now coming forward to corroborate some of these horrendous claims made by Arnold and others.
The White House responded by slamming the book and its author and chastising the press for writing about it.
She also puts forth a claim in the book that when she once brought Michael Cohen into the Oval Office for a meeting with the president, when Cohen left the office, Mr. Trump was eating a piece of paper. F**ing F**P! Disloyal! Fucking G**-g**'.
Manigault-Newman quotes Trump as saying: "Would you look at this George Conway article?" The two remain in contact, according to people familiar with the relationship.
Manigault-Newman's book "Unhinged" hits shelves next week.
"I didn't want to believe it", she writes.