Gibson's confession was the first time she has spoken publicly since - under fire from furious former fans - she told Daily Mail Australia she feared for her family's safety.
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The wellness blogger was a prominent Australian social media personality.
Her Instagram fan base ballooned after she "revealed" she had prolonged her life by embracing an alternative lifestyle.
Her "whole foods" business became famously successful.
Penguin published her recipe book and her app was to be offered on the Apple Watch.
But it all fell apart last month after revelations emerged Ms Gibson had failed to fulfil promised donations to various charities.
Friends then began to cast doubts about her cancer diagnoses.
She then tearfully "admitted" she may have been "misdiagnosed" by a "Dr Phil".
The Weekly insists it did not pay for the story and that it was approached by Ms Gibson's "people", the Melbourne "corporate advisory" firm Bespoke Approach.
Ms Gibson said her partner, Clive Rothwell, was sticking by her in spite of the controversy.
But she said he had taken a 'stern' line with her and insisted she play a straight bat.
"He's been very stern, along the lines of, 'I just want you to acknowledge where you've f***ed up and try not to smooth over that'," she was quoted saying.
In the article, titled 'My Lifelong Struggle With The Truth', Ms Gibson also said she had been forced to raise herself from the day she started school.
She said she took upon common household responsibilities, such as bringing her brother to school and making lunches. But she would not provide her mother's name or contact details to the magazine.
In her previous interview, Ms Gibson said she understood "everyone's anger and confusion".
But she took aim at many of her former fans who she believed had responded "maliciously" - claiming that her son's childcare details, home address and floor plan were published online.
Former friends had called upon Ms Gibson to "come clean" with the truth about her situation and had long privately questioned the veracity of her story.
Authorities told Daily Mail Australia at the beginning of April that Ms Gibson is still facing an official investigation.
A former friend of Ms Gibson directly called on her to "come clean" in an interview with Daily Mail Australia in March.
Mother-of-two Jayme Smith, 28, from Sydney, became a confidant of Ms Gibson's after they met on a parenting discussion page on Facebook around 2010.
They forged an online friendship and confided over their experiences with cancer - Ms Smith having lost her mother to lung cancer in 2003 and Ms Gibson saying she had brain cancer.
Ms Smith told Daily Mail Australia last month she was "baffled" when reports emerged this week where friends raised doubts about Ms Gibson's medical diagnoses and charity donations.
"I am just so shocked and I feel betrayed, that we all fell so hard for the illusion that she created," Ms Smith said.
"It has hit all of us, who I know, (who) also know Belle, like a tonne of bricks."
"We only knew her online, but we all believed to a point that she was a genuine pioneer, who was surviving aggressive cancer.
"Belle and I talked quite a bit about my feelings about (cancer), how she could empathise with me, the feelings I felt about my mother dying and how I'd wished I was more responsible when it happened, that I'd wished I had tried to explore more ideas, like Belle did."
Ms Smith said Ms Gibson "pushed" - and nearly convinced her - not to vaccinate her children, but that she did not blame her for nearly making that choice, which she "backed out of at the last minute".
"That was my own choice, based on information provided by Belle. I regret that choice (to nearly not vaccinate), but it was my own. I'm not here to place blame."
In November 2014, Ms Gibson told Sunday Style magazine she blamed the cervical cancer vaccine Gardasil for her cancer.
She told her social media followers last year her brain cancer had spread to her blood, liver, spleen, uterus and that she did not expect to survive.
After friends and medical experts cast doubt on her medical claims in various media stories this week, Ms Gibson told The Australian she may have been "misdiagnosed".
"It's hard to admit that maybe you were wrong," she told the newspaper, adding that she was "confused, bordering on humiliated".
The company she founded, The Whole Pantry, said donations to charities that allegedly failed to arrive had been "accounted for and not processed" and that promised donations "would be honoured".
Ms Smith told Daily Mail Australia she was "baffled" by this week's allegations and was most upset about the hope Ms Gibson's followers had invested in her program if she was being dishonest.
She said Ms Gibson had the "gift of the gab" and "needs to answer to these people (her followers), because they are good hearted people who deserve answers".
"I don't care about exposing Belle. I haven't spoken to her for months, years.
"I just want her to confirm or deny (her diagnoses) so people who put their faith in her, invested in her - they need to know.
"They need to know, if they've rejected conventional medicine on what she's saying.
"It's their lives, it's not a game."
