Well I have quite a bit of experience being lied to, unfortunately my woman was kind of a compulsive liar, she was so good at it I was with her for 6 years and married for two before I realised many things that if I had known to start with I would probably never even have gone out with her, at least not seriously.
Anyway, the liar force was strong in that one, so moving eyeballs and stiff arm signs or whatever were useless really. The only things mentioned here that are failsafe are points 1 and 9 of Vypros's: consistency and detail. I don't think there is any way you can tell if she's lying right away, but you can compare what she says about something to what she says later and see if they add up. The problem for liars is that while there is only one truth, there can be any number of lies made up to cover the truth, and all of these lies must be remembered...
So you need to ask for a little bit more information, about things that are seemingly unimportant, at least for the time-being. Get her to embellish the story, if the story is true you will be getting more truth, if not you will be getting more bullshjt. I believe in court this is known as extemporaneous detail, and every truthful witness should be able to provide it without hesitation. If the story was that she went out somewhere, well, did she go with anyone and where did they go, what time did they get there/leave/eat/drink, were they able to park on X street or did they have to walk from further away, was that ******* bartender there again etc. If the story is real, she will probably offer more details without being asked (the steak was too tough etc) but if it's a cover story generally the answers will be very brief and you'll need to draw it out bit by bit. But don't make this an interrogation, be nonchalant like you are not really listening much, and get into the habit of asking about things like this even when you are not suspicious so it seems more normal. If she thinks you are suspicious she will remember the story better herself later. Fishing for lies can work sometimes (oh, so did you see the (non-existent) car crash on main st?) but I find that jacks the suspicion level up too quickly.
If you already know at this point that some of the story is a lie, good for you. But if you don't, obviously what you then do is touch on bits of the story later on, after a long enough time has passed that the story has faded from her memory. "Hey what was that place you had steak at a couple weeks ago, let's go there." Perhaps not such a good example but you get the idea. A little bit of information can go a long way. When I first started dating that girl she was living with her parents, apparently. Then after a few months she moved into her own apartment. It wasnt until a few months after that when I was looking through the photos on my phone, I found one of her she had sent to me, but now I recognized her apartment in the background, but the photo was dated 3 months before she told me she had moved there. So I asked her again when she moved in there, and even though she
could actually still remember the bullshjt version and told me it again, I was able to impeach that immediately with the photo - immensely satisfying
And if you do find yourself with a liar like that, save yourself some stress and demote her to fkk-buddy status... it's not worth the hassle.
