Shark Tank co-star Kevin O'Leary had two big lessons to impart to the audience at the Inc.'s Iconic conference in Austin Wednesday night: the extraordinary commitment it takes to pursue an entrepreneurial passion, and how to sell your ideas to investors. 

A software entrepreneur who sold his first big venture for $4 billion, O'Leary knows plenty about the former. And having heard thousands of Shark Tank pitches in the past decade, the latter is second nature.

Notoriously blunt, O'Leary didn't wait long to say something provocative about the entrepreneurial life in a story about the advice he recently gave to a student.

"My fiancée came to me this morning and said she's going to break up with me," the student said. O'Leary says the man explained that he'd built a cloud-based compliance service for hedge funds and was bringing in $5 million a year in subscription revenue. He'd done it on the side while in school, and he found he didn't have enough time to give to his personal life. That morning, he said, his fiancée had issued him an ultimatum: Come to a picnic on Sunday or lose her.

O'Leary's response to the student: "Which one is easier to replace, the girl or the business?"

As the audience in Austin burst out laughing a little uncomfortably, O'Leary plowed on, saying he was simply being pragmatic. "The reason I asked that question is, if you're an entrepreneur and you're going to take that journey of self-sacrifice and put in all the energy that it takes, and the reason you're doing it is not because of money but the pursuit of personal freedom.... If your significant other doesn't get it, then I know you can find someone else who will love you very much"--rimshot--"especially if you're making $5 million a year."

His larger point wasn't lost on the crowd: If you want to succeed as an entrepreneur, you have to want it more than anything else. It's a lifestyle.

Moderator Kate Rogers, a CNBC correspondent, then asked O'Leary the question perhaps most on the minds of the audience members: Given all the pitches he's seen, what's the difference between a good one and a bad one?

"There are three attributes that are present in every single pitch that gets funded," he said. "Not some of the time, all of the time."

1) 90 Seconds or Less

"Be able to explain the opportunity in 90 seconds or less. 60 seconds or less is better," O'Leary said. "It has to be, 'This is what I do, this is why it works, and this is why it's a huge opportunity.'" He gave the example of Wicked Good Cupcakes, an unlikely Shark Tank investment because it was a non-proprietary, non-patented commodity product. "But these two women came up and said, 'We bake cupcakes. We put them in mason jars, seal them, and FedEx them to you as a gift.'" It was a good pitch.

2) Sell Yourself

"You have to be able to articulate why you are the best entrepreneur to execute on the business plan," O'Leary said. "Great ideas are a dime a dozen. Execution is really tough." When he hears a great idea attached to a not-so-great entrepreneur, he continued, he immediately starts thinking of ways to replace the entrepreneur. "So the real challenge is, if you have the execution skills, you have to explain that to investors. I used to work at a competitor. I tried this three times in a row and failed and now I know what to do. I worked as an apprentice overseas to learn the business. Or some other thing that makes you special--that's the story that makes you the right person."

3) Know Your Numbers

"This one is the killer," O'Leary said. "I've seen the air sucked out of a room in a nanosecond when somebody doesn't have this one. You've got to know your numbers cold. What's the size of the market, how fast is it growing, what's the break-even analysis, what's your margin? If you don't have the answers, you deserve to burn in hell in perpetuity."

He got another big laugh, but nobody missed the point. "You get all three of those together," he added, "you get funded. Always."