Very well. [And just as he's about to say something, he thinks of another problem.]
Of course, there is always the chance that you will claim anything I say to be false in order to make it seem as though I am the imposter. There is nothing keeping you from doing so and denying it would only leave us in the same situation we are currently in. Bringing in an outside source to verify would also be useless as it must be something nobody else would know.