Chosing to believe in something is the same as not believing in something and lying about it to others and/or yourself. You can't chose to believe in something. I can't choose to believe that a flying spaghetti monster created the universe.
...I think what he MEANS to say is that you can't choose to believe something just because it will benefit you, or just because you want to. Adam, you said in your previous statement that you believe in God because you
want to believe in life after death. I think what Cinesra is saying is that if you're only believing in something for an afterlife, then you don't really believe it.
Don't shoot the messanger, I'm just trying to translate. I don't think Cinesra literally meant "you can't choose to believe in anything" because you can choose to believe whatever you want lol.