Dean the megalomaniac control freak brother who demands to know every single detail of Sam's life, and who goes nuts if Sam leaves out a detail, shows what kind of dishonest hypcrite he really is. How many times has Dean gone bonkers if he finds out that Sam did not give him a detailed explanation of every dream, nightmare, memories, thoughts, etc.?
Sam is trying hard to trust Dean (big mistake), and tells Dean about Amy Pond (not the Doctor Who sidekick). Sam met her back when they were both children, and Amy saved Sam from getting killed by her Mom, a kitsune.
Amy is a kitsune who eats the thyroid glands of humans. She tells Sam she is working as a mortician so she only eats dead people. Kind of gross, but Sam lets her slide because she was the first girl he ever kissed.
After he tells Dean the story, and asks him not to pursue Amy, Dean agrees, out of love and respect for Sam. Pathetically, it turns out Dean is a lying sack, and he tracks down Amy and shows her no mercy, and betrays his brother Sam.
I would have liked this show better without Dean. Every time Dean got sent to hell or otherwise met Death, I hoped he was being written out of the show. Dean was an annoying character who always thought he was better than everyone else. His motto was "do as I say, not as I do."