The sassy, whip-smart investor was once rejected from "Shark Tank." Brian Ach / Stringer / Getty Images Barbara Corcoran has rejected plenty of contestants on ABC's hit show "Shark Tank," but the sassy, whip-smart investor was once rejected from the show herself.

When Corcoran was first offered a role on "Shark Tank," she signed the contract immediately and told everyone in her life she would be heading to Hollywood. Four days before she was set to fly, she was told by the production company that her spot had been given to someone else: a busty blonde half her age.

Devastated, Corcoran shame-spiraled. She kicked herself for ever believing that, at her age, she would be cast on a hot, new TV show.

Her private pity party quickly morphed into something else. "I did what I do best," she says. "I got pissed."

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The real-estate mogul wrote a brief email to Mark Burnett Productions and had an employee hand it to Mark Burnett directly. The email read: "I consider your rejection a lucky charm, because everything that ever happened in my life came on the heels of failure." Corcoran proposed that she compete with the other woman for the spot.

Burnett agreed, and the rest is history. "Five years, 37 businesses I've invested in — eight of which are hugely successful. Look at the wonderful second life I've given myself," Corcoran says.

This was just one story she recounted for the 600-plus business owners and entrepreneurs at Entrepreneur's Growth Conference in Miami last week. In a high-energy speech that drew many laughs, the outspoken 65-year-old said she had found that the ability to bounce back from hurt, rejection, and disappointment is the No. 1 predictor of a person's success in business.

"The difference between the real winners is how long they take to feel sorry for themselves. My winners feel it … but they come back up and say 'hit me again.'"

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Corcoran's life is studded with examples. In third grade, her Catholic school teacher Sister Stella Marie (or "the nun from hell") told her she wouldn't amount to anything if she couldn't read. Corcoran, who suffers from dyslexia, says she developed deep insecurities about her intelligence that remained with her well into adulthood. But those insecurities gave rise to her strengths.

Because reading and writing were a struggle, Corcoran became adept at expressing herself verbally. Also, because she fears being seen as "stupid," she pushes herself to learn as much as she can in an attempt to measure up.

"I have always had a real issue with everything that went on at that schoolhouse," she says. "Everybody's got their s--t, and that's mine. Anytime I do anything … I overprepare like crazy because I'm scared about failing."

Another example involves Corcoran's former boyfriend, Ramone "Ray" Simone, who provided the $1,000 loan she used to start a real-estate business in New York City in 1973. The two became business partners and spent seven years growing their company until Simone made the shocking announcement that he would be leaving Corcoran to marry her secretary.

At that point, running the business together became too emotionally overwhelming for Corcoran. One Friday evening, she told Simone their partnership was over. They divided their company and its staff in half. The following Monday, she moved into another office three floors above and started The Corcoran Group.

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Corcoran says Simone told her she would never succeed without him: "He gave me an insurance policy for life. I knew I would rather die than let him see me not succeed."

In 2002, she sold The Corcoran Group for $66 million.

Despite her "Shark Tank" fame, Corcoran still encounters situations in which she feels uncomfortable and insecure. If she walks into a cocktail party, for example, and finds herself booted out of a conversation, she can quickly feel those insecurities about her intelligence resurfacing.

Over the years, though, she has found a secret weapon — a two-word mantra that she believes everyone should tell themselves as they try to navigate the business world.

"It goes like this: F--k you," she says. "I have just as much right to be here as you. I'm just as smart as you. I've done a lot. I do this whole thing on my own. And I'm so grateful I had to come out of that hole to do it."