In two ways ... many Baha'i adherents have been to this forum before, and each have said the same thing ... that Baha'ullah is the real deal, and that we have proof. You're still new here, and I was pointing that out to you. So it just seems so repetitive to me.
The other thing is that other religions or groups say the same thing ... "Our faith is the real deal and we can prove it." Mormons, Jehovah's Witness, Satya Sai Baba followers, Meher Baba followers, Ammadiyya Muslims, Muslims in general. Christians in general. Even individuals about themselves, and we have a coupld of those on this forum. (Not all to be sure!) So it's not a new message ... the idea that 'I have the truth, and I can prove it."
So imagine a circle of people, 100 strong. Each in turn steps forward into the middle of the circle, and yells out the the others ... "I have the proof and I can prove it." Once it gets through all 100 people, it just starts over, and continues going round and round, nobody even seeing the other 99 people.
Then, back on the hills overlooking this entire thing are a few more people, just watching, and watching, and hoping somebody steps out, or notices someone else, that there is some shift in the pattern, but there never is. So eventually the watchers just give up and go home.