It's the analogy of experience that I want to point out.

>I have a colleague who believes that he has encountered aliens from outer space (well, at least seen & experienced a UFO at fairly close quarters) - does that mean that for him, aliens do actually exist ? Or would you suggest that he may have been mistaken, if so, then I would have to question your experience.

No matter how wonderful my experiences are, you will not believe it either. But once you have your own personal experience with HIM, you will absolutely believe. If you want, try asking God that if He really exists, He'll make miracles in your life. But don't make God a genie.