Usually, during an inspection from a health authority (e.g. FDA, EMA, etc.), there is no need to prove that the information and data you are presenting is legit. If the inspector has these doubts, it is most likely that he has seen data integrity issues during the inspection; and when an inspector sees data integrity issues during the inspection, the audit is practically over (failed), since he will have objective evidence of data integrity loss, and will question all other data that had been presented for review.
In short, I suggest that instead of looking for ways to prove you are being honest on doing your due dilligence, it is best for you to ensure that yout integrity test records are robust by demonstrating data integrity in those records, so that its integrity is not even questioned.
There are plenty of guidelines issued worldwide related to data integrity, if you want to get some ideas to consider to make your records compliant with Good Documentation Practices (GDP)
I hope this suggestion is helpful!