Nigerian Romance: Your new online beau is tall, dark, handsome – and a fraud.

If you're a single, 40-something woman who's wasted one too many bikini waxes on the wrong men, a message like this in your inbox might seem like a gift from Cupid.

"Hello Pretty!!! How are you doing? I'm Frank. From Virginia. But am New to the State's...The first thing that came to my mind when i saw your picture was..'WOW..you're drop dead GORGEOUS, that is why i'd took time to introduce myself... Well i am currently in west/coast africa working on a Casino project at this time... I have 2 weeks to get back to the state. if you are interested and you will like to talk some more."

So he's not the greatest writer. But you've recently figured out, thanks to many chats with girlfriends and your mother, that you've always been too picky anyway. That's why, at 43, you're still single.

You've also been at this online dating business for months, and though you've always sworn off anybody who wasn't local, you spent enough first dates at Ruby Tuesdays to reconsider.

You're a college-educated career woman. You don't need a man to fund those jaunts to Europe or help with the mortgage. But it wouldn't hurt to find one who could match your enthusiasm for the finer things—someone who's financially secure, thoughtful, funny, good-looking and, most important, crazy about you.

Frank Cotton? From his pictures he's a real beefcake. Tall, athletic, good-looking, employed. The kind of guy who loves life, traveling, working hard and playing hard, who just needs a feisty gal like yourself to share it all.

But right now, he's wooing you with his life story, the promise of far-flung locales and his favorite Van Morrison song, "Someone Like You." Over the next few months, he'll wake you up with romantic text messages and instant message you all day long. He'll ask about your day, laugh at all your jokes, and make you feel like the only woman in the world. You'll burn the midnight oil on the phone at night, where you'll learn about his dead parents, his inheritance managed by a stingy aunt, his passion for architecture, and his dreams of marriage and children. It all fits together with cinematic significance.

But one day, after weeks of romancing, he calls you, frantic. He's trying to ship some antiques out of the country and the export fees are exorbitant, but he's a little strapped for cash. He's embarrassed to ask, what with him being a successful architect with a sweet inheritance, but he'll pay you back immediately—and it's just this one time.

Only it won't be.

At the end of six weeks, your Casanova will drain you of a cool $7,000. And compared to the other women he's swindled, you're getting off easy. An Internet search for "Frank Cotton" and "Nigeria" leads to a site for the romantically scammed, where multiple posts share tales of the man who bilked them all for thousands.

It happened to Jill, a 43-year-old Nashville woman working in finance. That's not her real name—she's too embarrassed to tell her family about her astonishing naïveté, much less go public. With her shiny shoulder-length hair, voluptuous figure and well-tailored wardrobe, she looks every bit the part of the modern career woman you'd spot downtown sipping a chai tea while texting on her BlackBerry. It's hard to imagine that this fast-talking, bright-eyed woman with a casual sassiness could be so easily snowed by a schemer pulling one of the Internet's most notorious cons: the sweetheart scam.

It's a variant of the 419 scam, named for the Nigerian law code outlawing fraudulent practices that promise unclaimed millions in exchange for a little dough and a little risk up front. But thanks to the proliferation of online dating sites, now any lonely heart with a little bit of savings is a perfect mark for swindling. Only the big pot of gold isn't a financial investment. It's the hope of companionship, true love and marriage.

These lotharios create fake profiles on dating sites like Match.com or eHarmony, usually pulling photos from European modeling sites. Then they browse for women—single women with high incomes, particularly those who look vulnerable or were recently dumped. The kind of ladies desperate to have their faith in romance restored.

The backstories are eerily similar—a guy from the States is working in construction overseas. He's a successful entrepreneur who runs into a little bad luck. A passport error keeps him detained in the country. He can't cash his paychecks till he's back home. He often has bad money orders he needs you to cash for him, offering to let you take a little off the top for yourself.

The excuses may vary but the MO is the same: He needs just a little dough so he can get back home to meet you in the flesh—his princess, his dream girl, the most gorgeous, intoxicating woman he's ever encountered.

"I fell for this guy over the phone," Jill says. "He would say all these sweet nothings that I totally wanted to hear. I'm 42, I've never been married and wasn't in a relationship. So I was like, 'Wow.' "