if a person believes in “Moshe Emes v’Soraso Emes” where is there room for doubt?
As far as proving it’s total truth beyond a reasonable doubt, it is possible-read “Beyong a Reasonable Doubt” as I have been suggesting in past posts, as well as “Permission to Receive” by Lawrence Kellemen–awesome reads, and gives a great deal of peace of mind when one comes to the point of realizing that Hashem and His Torah are absolutes in Truth. I deal all the time with people who aren’t interested in the dogma, as I’m sure most who are seeking this answer aren’t, but it’s worth your time to read these as they deal with the intellect.