Fixing your reputation is slow on purpose. People need to see the new version enough times to believe it.

People update their picture of you slowly, and that is not them being cruel. A reputation is a prediction, and predictions only change when new evidence keeps arriving, which takes more than one good week. You can feel completely different inside long before anyone outside has enough to notice.

Decide what you want people to be able to count on from you, then do that one thing repeatedly without announcing it. Skip the speech about how you have changed. Let the tenth time be what convinces them, because the first time never does.