My girlfriend failed a professional exam what should I say?

Tell her that it is not the end of her world!!! she will be understandably very upset so remember to be a good ear as this will be what she will need! Highlight the fact that a high percent dont pass FIRST time and that surely she can sit it again?!? Remember that also the experience of not achieving something you want is a good learning curve and future employer will like someone with good life experience :D also be there for her as her BF too by making dinner for her coming home or something!

I would just tell her she is a smart girl and that with a little more studying maybe she can pass it next time since she knows what it is going to be like now. Also, maybe tell he you will help her study if needed. Just try to keep her confidence up and don't let her think that she is a failure. She knows that not many people pass, but tell her not to give up! Hope this helps!

Buy her flowers, show her in some way that you care, and just let her know that there's always a next time, to not be hard on herself, and to not give up!!!