“It is now of paramount importance to me to say, from the bottom of my heart, I am so sorry,” she wrote.
NXIVM founder Raniere was sentenced last October to 120 years in prison for his role in leading the criminal enterprise that included a cult-like sorority where women were sexually exploited and branded with his initials.
The former actress is expected in court Wednesday for sentencing.
She added: “Please know that I am dedicated to spending my life working to mend the hearts I broke and continuing to transform myself into a more loving and compassionate woman.
Last summer, the HBO docuseries “The Vow” explored how Raniere and co-founder Nancy Salzman manipulated others into joining what they thought was a self-improvement organization.