People feel that other doubt them because they give them a reason to doubt them. Why you feel fear or be afraid if you know what you are doing is right and good. Why would you entertain the idea that people gossip about you if you actually not doing that to others.
People doubt what others think of them because you are a culprit of those negative ideas and emotions.
If you do good, and you do things right, there’s no reason to fear nor doubt. Confidence is not given by others telling us we are good. Confidence is a conviction of doing good and doing it right.
There’s no cure for doubt. You start with the end in mind…doing what is right and standing up for it.