In Sin City; A Dame to Kill For – opening Friday – Alba reprises her role of Nancy Callahan, a former damsel in distress who's seeking retribution over her dead protector, John Hartigan (Bruce Willis).
As a working mom of Honor, 6, and Haven, 3, Alba can especially relate to her character's fearlessness.
"I don't have anything to lose," the actress, 33, tells PEOPLE. "I feel like I've done all the hard work. I really was married to my work for so long that I've kind of been there, done that. I was ready for a new phase in my life."
She adds, "When I became a mom, I just kind of opened up and got a new perspective. I have a fearlessness and a confidence that I think you can only get with experience and age. Some people get it earlier, but it took me a while."
Alba's outlook on life definitely helps with her other role – as CEO of The Honest Company. When asked if it's nice to have a job that doesn't require her to look camera-ready hot all the time, Alba laughs and says running a business that sells eco-friendly baby products can also be sexy.
"What's great is that when you're older and sexy, you're not really just a one-trick pony," Alba says. "There is so much more that goes along with it. Intelligence is sexy, confidence is sexy, knowledge is sexy. At work, I'm wearing a completely different hat. It's a pretty creative environment, but there's a lot of data and analytics, a lot of boring meetings, just straight business stuff. It's cool, though!"
That begs the question: Which one of her daughters is more apt to run a company, and which one seems more likely to follow in their mom's showbiz footsteps?
"Oh gosh, I don't think either of them are going to be actresses, if I can help it," Alba tells PEOPLE. "Maybe Haven will be a filmmaker because she's more creative. I feel like Honor can have more of the business sensibility."
For more on our interview with Jessica Alba, pick up the latest issue of PEOPLE, on newsstands Friday