A millionaire CEO who was once homeless says these are the 3 most important lessons he's ever learned

The single most important lesson Sandoval has learned, he says, came from a coworker during his time as a stereo salesman.

Sandoval says he had always been the best salesman at any job he took...until he worked with Mike.

Mike sold the most stereos every week — even when he was on vacation — because people trusted him.

Sandoval had been trying to sell stereos by describing all of its features, but Mike just walked up to potential buyers and said, "Oh my god you're gonna love the way this sounds with that other stuff I sold you! This is just fantastic!" And they would go, "Okay Mike, I'll take it" because they trusted him.

Sandoval says this was the number one lesson he took with him to Purium Health Products. "When I started my company I said the number on thing that I'm selling is trust."

He knew if people trusted him, then they would believe him when he said, "These products are 100% pure."

Later, after he had started his company, Sandoval became a regular guest on different radio shows in New York. He says when listeners called in, the radio station would often ask them, "Why do you listen to this show?," and they all said one thing: "Because we trust Dave."