It took Uncut Gems directors Josh and Benny Safdie years knocking on doors in Manhattan’s Diamond District before anyone would give them the time of day. It’s a neighborhood—really a couple of blocks, located just off Times Square in Midtown Manhattan—where millions of dollars change hands every day, and so the people making the deals are understandably a little wary of outsiders. It’s the perfect setting for the year’s most stressful movie, which features Adam Sandler as Howard Ratner, an irresistibly irritating diamond dealer and compulsive gambler. And as it turns out, the best way to win over the Diamond District is to learn how to strike some deals of your own.

Roman Persits, a jeweler who has worked in the district for more than 40 years since he left the former Soviet Union in 1975, will be the first to tell you the area can be a little impenetrable for strangers. “I think it took Josh close to three or four years before people started letting him in,” he told Vanity Fair in a recent interview. “Because people are very apprehensive…For an outsider, it’s a job and a half to get in.”

For all the years the Safdies and their producer Sebastian Bear-McClard spent stomping the pavement, Persits had heard nothing of the film when a casting director saw him downstairs from his office smoking a cigarette last fall. As Persits recounted to the New York Post and VF as well, he returned to his office to find the Safdies and some crew members waiting—and they had mostly convinced him to participate by the time the real dealmaker showed up on Monday.

Adam Sandler arrived unshaven, wearing a T-shirt, basketball shorts, and dark sunglasses, and at first Persits didn’t recognize him.

“He folds his hands, looks at me straight in the eyes, [and says], ‘So you are the famous Roman…. I hear you don't wanna be in my movie?’”

Roman Persists with Adam Sandler (left) and Sebastian Bear-McClard (right). Left by Mackenzie Samet, right by Todd Vulpio.

Like many other jewelers in the area, Persits later showed Sandler the ropes of making jewelry, while Todd Vulpio, with whom Persits shares an office, shared the ins and outs of being a salesman. Izzy Aranbayev, CEO of Avianne & Co., got involved thanks to an introduction from rapper Cam’ron, but wasn’t immune to Sandler’s star power, either. “Everybody’s a fan of his,” Aranbayev said. “I’ve been watching him since I was a teen.”