Bill's POV:
She finally fell asleep. So I decide to go into her dreams. Her dream turns the gray and she turns to look at me, her pure horror becoming obvious in her face.
"W-who are you?" She asks.
"Oh, how rude of me. My name is Bill Cipher." I say nonchalantly.
"Dipper told me about you! Stay away from me, y-you monster." She shrieks, cowering away slowly.
   "My dear," I start. "I have no intention of hurting you." She stops cowering and stands straight up, cocking her head in confusion. "I simply want to make a deal with you." I smile, hoping to get in her head a little bit.
   "What kind of deal?" She asks. Good, I've got her interested, I think.
   "You get me what I want, and I'll give you anything you desire."
   "Like a genie?" (Brought to you by Patrick Star) She questions.
   "Um..sure."
   "What is it that you want?"
   "Dipper's journal." I smirk. She gasps,
   "Are you crazy?! Dipper and Mabel are my best, and only, friends. You expect me to throw them down the creek like that?! You're nuts." 
   "It's the perfect plan." I chuckle. "They won't see it coming! You steal the journal and they'll never expect it was you."
   "There's no way I'd ever do that to them!" She yells.
   "Not even if it meant......seeing your mother again." I grin evilly.
   "How do you know about my mother?!" She shrieks.
   "I am a demon, and demons know all. I know that your mother died when you were 13. However, if you get me the journal, I'll let you see her again." I suggest.
   "You're lying!" She yells angrily. "I know that you'd just rip me off even if I did agree to your stupid deal!"
"My dear, I'm not lying. Just get me the journal, and I'll let you see your mother." I say calmly.
   "You promise?" She says, glaring at me.
   "I swear." I say, raising my right hand.
   "Then you have a deal."