Despite your sincerest efforts, people will doubt you. It happened to the Apostle Paul. He was accused of being a false apostle because he didn’t want gentiles to get circumcised. (He was vindicated by the head honchos in Jerusalem, but still itinerant preachers cast doubt over his person.)
If it happened to Paul, to Job, to Jeremiah, to Daniel, to Amos, to David, to … to JESUS, why be surprised if it happens to you.
This is not to say that you, or anyone, is perfect. It is only to say that we live in a fallen world, and we are not the only ones to possess a cynical sin nature. Others can view us how they want.
In those moments, may our God strengthen us to keep fighting the fight of faith, to keep trying, to not give up.