An apology isn’t finished when the words end. It’s finished when the behavior changes.

Words open the door and behaviour walks through it. An apology is a promise about the future, so until the future shows up, all anyone has is a statement. The person you hurt is not being stubborn when they wait to see what you do, because they are reading the only evidence that exists.

After your next apology, name the one specific thing you will do differently and then do it where they can see. Do not announce it again. Let the change be the message, and let them take as long as they need to notice.