No offence but how old are you? I wish things were as straight forward as a box of chocolates and some flowers on the first date... things don't work like that. I don't accept her answers because she changes her answers all the time to the same questions. It seems she lives in the moment.
I'm not really sure what my age has to do with anything. But since you ask, I'm 38 (does that make my opinion more or less valid?). I don't think I ever suggested buying her a box of chocolates and some flowers and everything will be ok - far from it.
No-one can read your girlfriends mind, no-one. No-one can possibly know whether she is capable of loving, or having feelings. Only she knows the answer to that. Not you, not me, not anyone else on this forum. PTSD can leave sufferers feeling numb, and lacking in emotions, but as I said before, PTSD symptoms have varying degrees in every sufferer, so it's impossible to answer on an individual basis. Perhaps you should take her word for it?
Its hard to take such drastic advice from some name and box of text on my computer screen
You asked for advice and I have given you my opinions. You can take it or leave it, it's only my opinion.
I will give you my final opinion. I don't think you are willing to accept answers that don't suit you, both from people on this board and from your girlfriend. You seem to be convinced that you can 'save' this girl and 'fix' her. Maybe she doesn't want to be 'saved' or 'fixed'. Maybe there is nothing 'wrong' with her. Perhaps she doesn't have PTSD at all.
You and her 'diagnosed' her as having PTSD. If indeed she does have PTSD, you can't pick and chose which symptoms she has just to suit you. You have read the diagnositic criteria, and quoted it, so you know the answer to the following question.
What I hope is that PTSD doesn't obstruct in ANY way a person's ability to form feelings of infatuation/love etc
Yes, it can and it does, but not for all PTSD sufferers. I think you need to learn to accept what she says, stop trying to read her mind, stop trying to guess how she feels. And accept her for who she is, and what she tells you. Either accept the relationship/friendship for what it is, or move on. Again, just my opinion which you can take or leave.