Sean Lowe's squeaky-clean persona mystifies Desiree Hartsock's family in the Feb. 18 episode of The Bachelor. When the devout Christian insurance agent visits the bridal stylist in her hometown of Sherman Oaks, Calif., the former fitness model makes a wrong impression with Hartsock's brother.

"So far from being here, what I've seen from you, I believe that she's really into you, but you're not into her," Hartsock's brother says.

Though Lowe insists he's "crazy" about the 26-year-old brunette, Hartsock's brother isn't convinced. "I think your'e just a playboy," he argues. "You're just having fun with the circumstances, just whatever comes along."

Confused, born-again virgin Lowe apologizes for getting off on the wrong foot. "I'm sorry I gave you that opinion, but that's not me -- at all. It's not me," the 29-year-old Texan reiterates. "I don't think you're buying it, though."

"Not at all," Hartsock's brother says. "I'm not buying it, not what you're saying. No, not really."

The Bachelor airs Monday at 8 p.m. EST on ABC.