For the women—many of whom hail from Medellín's poorest suburbs—the lure is simple: free drinks and the chance to meet a foreigner serious enough about love to pay for it.

Today, Dave's job is part cultural concierge, part cheerleader. The latter proves vital. For many men, booking this tour isn't without emotional consequences. The process forces an admission of defeat: that they still haven't figured women out. Dave is a counterweight to these insecurities, a quippy, encouraging ally.

Who are the women, then? Quite a few come from the poorer parts of Medellín—like Comuna 13 and La Iguana—and many are single mothers. "The girls want to get out of the country," says Howard, a 57-year-old agricultural entrepreneur I met on the plane and who, coincidentally, married a Colombian woman a decade ago (though not on a matchmaking tour). Having traveled regularly from San Diego to Colombia to court his wife, Howard had the opportunity to see the tours evolve over the years. "They have looks, they're beautiful," he says. "But if they hit 25, 26 . . . the boat has left the dock. They're too old for Colombian guys." For these gals, the appeal is simple: free drinks, free food, and the chance to meet a foreigner serious enough about love to pay for it. Throughout my trip, several young women would complain about Colombia's notoriously unfaithful men.

One tour participant, passing through the hospitality suite, stands out when I first see him: Jack (his name has been changed here at his request) doesn't hesitate to introduce himself. He spent years as a ballroom-dance teacher and continues to take African-dance classes. His chest is accentuated by a tight black T-shirt, which is tucked into green chinos. His arms are circled by tattoos; a black trucker hat hides bright turquoise eyes. The underside of his hat reads: make your own luck.

With newfound confidence from his time in Medellín, Jack became a repeat client of the tours.

"American women," he sighs, "are not very nice. I've suffered." Jack has a golden tan that comes from having lived in the American southwest for two decades. His voice sings with theatricality and sweetness. It is a shock when he reveals his age: 52. He looks at least a decade younger. Probably because he weighs the same as he did when he was 20. Or maybe because he scrubs his face with sea salts. Jack has been burned—by a dancer from California. She moved in with him and ended up sleeping with a friend. He hasn't dated in the four years since. After trying Match.com, he discovered AmoLatina.

"I'm not very tall. I don't have much hair. And those things really do matter: First impressions matter," he says. "If I go to a bar, especially a crowded one, there's going to be a lot more men than women." Larry, my AmoLatina chaperone, nods in agreement. "And I'm a small guy. I want to sit in the back, in the corner, against a wall."

• • •

Back at Dulce Jesus Mio, it doesn't take long for the dozen foreign men to find themselves blissfully surrounded—by approximately 150 women. The team of translators gets to work, dragged from table to table by the men, in part to bridge the cultural divide. Assertive women, meanwhile, begin to edge out their rivals: cornering men on the move and grabbing translators for clandestine conversations. The guys are outnumbered 10 to 1. It is a rare moment for them; they are the commodity.

Aguardiente—firewater—the potent, ouzo-like Colombian liquor, begins to flow. Jack entertains a table of women, emphasizing his points with flourishes of the hands and then listening to the responses with distinct intensity. The fellas are engaged with two, three, or four women at once. The scenario is rousing a swagger that many of these guys had lost years ago (or maybe never even had).

I seek out an interpreter for my interviews—it is clear to all that I am a journalist—and meet Laura, a petite translator. As the club grows humid, I'm introduced to two women: one 22, the other 30. The younger says, via Laura, that her ideal man is tall, white, and at least 20 years her senior. It's their first time—they heard about it on the radio—and, with muffled giggles, they ask to be introduced to some of the Americans. "I want to meet a man who can dance!" says the older woman. I tell them they should meet Jack, who is still diligently engaging with a table full of girls. I promise the two an introduction later.