I cannot communicate to you the full evidential impact that my experience has on me but that doesn't mean that you cannot communicate to me evidence that would act as an undercutting defeater to my belief. For instance, let's say that I say to you that I have this experience that has led me to believe that I am really interacting with Christ; you, being the suspicious sort , do some digging around and find that my wife has been putting mind altering drugs into my food for the last five years because she is worried that I am going to become an atheist. Presenting me with evidence like that would give me pause to consider the origin of my belief.
I don't know if such a machine even exists, but if it were possible to demonstrate to you the increase in endorphins your brain receives whenever you think about how much Jesus loves you, would you consider that evidence enough? Because that is the how an emotional response to positive stimuli works. Its almost like the mind-altering drugs in your food example you gave above.
In another thread, I used the example of a schoolboy receiving a note saying "I love you and want to be your girlfriend" from a beautiful classmate on whom he has an enormous crush. His passionate emotional response would certainly be a wonderful sense of euphoria which would be very real to him, so long as he remains unaware that the note (and the girl's affection) was intended for the boy seated at the desk behind him.
I would never dispute that the emotions
you experience as a result of your beliefs are certainly real. I'm simply saying that one's emotions can be easily manipulated by something one really wants
to be true, even when that thing is anything but.