"I always knew I wanted a great man of God, someone who was going to be an inspiration for people and also be a lovely husband and father," the pop star, 26, tells Harper's Bazaar in its December issue, on newsstands Nov. 23.
She adds: "I also definitely wanted to have a laugh. I have all that in him."
Brand, 35, first achieved notoriety in England as a hard-partying comedian, but later had a spiritual awakening and got sober after years of heroin and alcohol abuse. A decade older than his California-born wife, he's traveled a longer road – but she says they're still a perfect fit.
"We're at different places in our lives, but we can still grow together," she says. "He's thought-provoking, articulate, a real advocate."
Perry says she wrote the ballad "Not Like the Movies" about realizing that Brand was the one. "The song is an encouragement to others," she says. "They don't have to settle for anything besides spectacular."
Asked about her own image – in particular, how she uses her sex appeal to her advantage – Perry admits to walking the line between being wholesome and not so wholesome.
"I'm kind of a good girl – and I'm not," she says. "I'm a good girl because I really believe in love, integrity, and respect. I'm a bad girl because I like to tease. I know that I have sex appeal in my deck of cards. But I like to get people think ing. That's what the stories in my music do."