You can tell she's faking it if she bucks like crazy or screams out like she's out of her mind, or if she uses too many words to tell you she's coming. A girl who is really coming will be too lost in the heavenly sensation of her physical upheaval too say or do much of anything except moan and cling to you with a vice-grip, like she never wants it to end.
Here's something else. No matter what girls say, when it comes to sexual intercourse most of them fake their orgasms. The only way they can come is by having their clits stroked or by being eaten out. Like it or not, that's how it is in the real world.
Now every woman's response is different, some will utter a few words, some will moan and some can't help but scream and buck that's real, it could be fake, sure but there are times where the screaming and bucking is real. Some women are well aware that this kind of "extreme" response may be interpreted as exaggerated or fake and have to make great effort at toning it down, indeed it does hold them back from going over the edge. Some women are afraid of losing control cos men like you will misunderstand it.
