Like you said there can't be multiple true faiths that conflict with each other. There's only 1 Bible that's the most widely available book which contains explains fully the past, present, future. It is also scientifically and historically accurate and contains fulfilled prophecy. In the Bible God tells you what happened, what he's doing about it, and what the result will be. Also there's only one hearer of prayer that would care whether people want to listen to him (Psalms 65:2, 2 Chronicles 16:9). If you pray to him with sincerity for guidance and he answers you by helping you understand his Bible and learn more about him that would certainly provide evidence.