The socialite has had a string of high-profile romances with the likes of rocker Benji Madden, Greek shipping heir Paris Latsis and Doug Reinhardt - and each one appeared to be very serious.
But after dumping club boss Cy Waits earlier this year (11) after an 18-month romance, Hilton admits she's troubled to find herself alone at 30.
In a new interview with Life & Style magazine, she says, "When I was a little girl, I always imagined I'd be married with kids by now. It's not where I thought I'd be. I'm 30, and I'm by myself."
And she admits that she realised Waits wasn't "the one" while watching the first episodes of her new reality TV series The World According to Paris: "By watching the show, I got an outside perspective of our relationship."
She reveals she saw another side to her then-boyfriend in scenes in which she'd thought Waits might propose, and how he dealt with a pregnancy scare.
She adds, "I realised that yes, I love him and he's one of my best friends, but I needed to make sure he was the one. When I realised I wasn't certain, I knew I had to end it."
Hilton is now more determined than ever to find new love amid reports she has moved on from Waits with moviemaker Todd Phillips: "I want to be married and pregnant in two to five years, but first I have to work through my trust issues."