"It's all about winning," the source told Us Weekly. "She wants him to chase her and will do anything to get his attention."
Krystal, a 30-year-old fitness coach from Montana who currently resides in San Diego, CA, received a memorable one-on-one date with Arie early in the season in which the Bachelor brought her home to explore Scottsdale, AZ, and then introduced her to his parents, younger brother and sister-in-law.
Krystal found herself above the competition after that date and felt no one's connection with Arie could ever compare to her own. She called the other girls "juvenile" and "obnoxious," but they in turn viewed her as "condescending," "fake" and "two-faced."
Although Arie was warned by a couple of women about Krystal's behavior on The Bachelor, the source said Arie saw Krystal as being "emotionally ahead of the other women" since she "knows his family" and therefore probably "knows him best."
But drama will reportedly escalate to a whole new level during the upcoming January 29 episode when Arie and a group of women enjoy a competitive-bowling group date in Fort Lauderdale, FL.
"Krystal gets mad when Arie invites all the women to an afterparty originally meant just for the winners," a show insider told Us. "She calls him a liar, locks herself in her room and refuses to come downstairs."
Krystal's little tantrum, however, works to get Arie's attention and affection.
Noticing her absence, "Arie gives in and goes to find her," the insider added. "Krystal wants Arie to seek her out in a crowd -- she doesn't care what the other women think of her."
And Arie apparently doesn't view Krystal's emotional state and vulnerability to be an issue, at least at first.
"He doesn't want to shy away from talking about their problems as a couple," the insider told Us. "They butt heads but they see that as something that brings them closer.... She questioned his character but he can't get past how well she knows him."
"All my stuff is packed," Krystal tells the girls in the promo.
Once Arie confronts Krystal about what's upsetting her, Krystal sweetly comments, "Aaww, our first fight," but then Arie -- with a straight, unamused face -- bluntly states, "It could be our last fight."
Krystal is then shown venting to cameras in a confessional while pretending to throw glitter, "I'm f-cking over it. I'm done!"