I want to know how she went from calling him a liar and wishing to go home so fervently, to being gung ho about infiltrating and destroying the Losties.
I was wondering about that as well....
She REALLY did want to get off the Island, and she wasn't a bad person in the first place. I wonder what made her go along with the plan.
I could be completely wrong, but I think Juliet just went with Ben's plan because she wanted to find a way to detach herself from the Others, without actually making it obvious that she's straying away from them. It's obvious she's desperate to return home, and holds animosity towards Ben for not letting her do so. She keeps saying "I'm on my own now"....like she's not on the Others side anymore, or on the Losties side (yet) either. She's trying to figure out exactly where she belongs on the island, and sooner or later she will. When Ben meets up with her in a week like he said, I don't think Juliet will end up going with him/the Others. But yeah, that's just my theory.