For four years, a woman who called herself Anna Delvey and claimed to be a German heiress lived in luxury hotels in New York City, dining in some of the city's best restaurants, partying in its best night clubs, and bilking both friends and institutions for a total of $275,000. She announced that she planned to open a combined artist's center/exclusive club in a historic Park Avenue building, and came close to securing a $22 million loan for that project. She was eventually arrested after ducking one hotel bill too many, leaving behind an impressive trail of unpaid loans and fantastical excuses. Her story is a cautionary tale for everyone about who we choose to believe--and why--both in business and in life. 

Delvey (whose real name is Anna Sorokin) has been a source of intense fascination ever since her story was first reported. She's the subject of a major feature in New York Magazine, a Vanity Fair confessional by one of her duped friends, at least three books, and most recently a nine-part Netflix series created by Shonda Rhimes, of Scandal and Grey's Anatomy fame.

Delvey's story raises some tantalizing questions. How did a 23-year-old manage to create this fictional alternate reality and make it seem so real? Where did she get the $100 bills that she famously tipped with in luxury hotels? And especially, how did she keep the charade going, constantly borrowing from new sources to pay off old ones, for four years?

Some would ask the question that my husband posed as I sat binge-watching the Netflix series: "Why does anybody believe someone like that?" That's the only one of these questions I can readily answer, not because I've ever met Anna Delvey or traveled in the stratosphere of wealthy New York society, but from my own experience. Years ago, I got sucked in by someone who also claimed to come from a wealthy family--Peruvian, in his case. And though I didn't lend him large sums of money or hand over my credit card, I did something equally disastrous--I married him.

What Anna Delvey has in common with my ex-husband.

I know why suckers like me buy the improbable tales told by people like Anna Delvey or my ex-husband. We believe them because we want to believe them. We really, really want to live in the world they seem to be promising. We want to see how the really rich live, we want their attention and their friendship, and sometimes their love. Despite their supposed wealth, they often come across as lonely or sad, and we feel envy and compassion in equal measure. It can be a powerful mix.

Ultimately, we don't just get deceived by these charismatic liars. We also deceive ourselves by believing what we wish were true. This explains why, after more than a month of increasingly improbable excuses, Vanity Fair photo editor Rachel DeLoache Williams continued hoping that Delvey would refund the $62,000 charged to her credit card for a luxury trip to Morocco that the supposedly rich Delvey had said would be her treat. This is why, for way too long, I believed that my ex-husband came from a wealthy family even though I was never allowed to see where he lived.

It's not that we're fools, or at least not only that. It's that we're up against our own brains. Multiple studies show that humans are biased to believe things we want to be true, and to expect things to happen the way we want them to. The more we want something to be true, the more willing we are to believe it, even when there's plenty of evidence that it isn't. The danger of this bias becomes obvious when people like Williams and me get taken in by people like Delvey or my ex-husband. But there's an even bigger, though less obvious, danger when wishful thinking bias leads people to believe that climate change isn't real, or that real estate prices will never fall. Or, that a new company, new product, or new investment is sure to succeed even if the numbers suggest otherwise.

How to fight cognitive bias.

How do we overcome this brain bias? There's only one way, and it isn't fun. For every time you decide to believe a sales rep's promise, or a lover's declaration of fidelity, or an employee's assurance that a problem is under control, ask yourself this simple question: How much do I want this to be true?

Be very, very honest with your answer. If you truly don't care, or don't care very much, you're in much less danger of being deceived. But if, as is often the case, you have a very strong desire for something to be true, then you need to explore further. Ask yourself what evidence you have that it is true, and what evidence you have that it isn't.

Most important, ask yourself this: What if it weren't true? What would you do? What changes would you make? This is what led me to stop finally taking my ex's statements at face value and start fact-checking some of what he told me. It's also what finally led Williams to reach out to law enforcement and report what Delvey had done.

None of this is easy, not for Williams, not for me, and not for you if wishful thinking bias has led you to take dangerous risks or ignore dangerous problems. But you have to do it. Because there's one thing we all know: If you convince yourself something is true and it isn't, sooner or later that lie will come crashing down. And if you don't protect yourself, it could bring you down with it.