Okay, now I am really lost*. My point was, simply, that something that is probably a lie, told by someone we know to be an extremely good liar, shouldn't make you think "Hang on, how could she know that? This is stretching it a bit." but, surely "Another lie from The Others. And Jack's buying into it - they're wearing him down." (Or something vaguely similar) *shrugs* That's all, as you say it's your call in the end. I'm just clearly missing something in your thought progression.

* Edit: Lol pun.