The former Bachelor winner, 24, still has reservations about getting close to anyone, based on what she calls a "train-wreck" experience with her former love.
"Even opening up to Kasey, like, we were dating for a few months, but I didn't want it to go public because I wanted to make sure it was real," Girardi told PEOPLE this weekend at Reality Rocks Expo in L.A. "I am absolutely scared of the possibility of getting engaged again. It scares me 100 percent."
Luckily, Kahl is putting her at ease. "Kasey is genuinely a nice, caring, loving person, even when the cameras are off," Girardi says. "That's what makes the difference. When we're at home eating dinner or watching a movie, he's still that sweet charming guy that he is when we're out in public. I want someone who is going to love me unconditionally, all day every day – not just when other people are seeing it."
Kahl was equally hesitant at first about dating Girardi.
"I told myself I'd never date someone from the Bachelor franchise, but I met her, and everything went out the window," he says. "She's amazing. No matter what we've gone through, and no matter what she's gone through, I'm here now, and I will make sure she's the happiest girl ever."