People notice who answers in a day and who answers in a week. Reliability is mostly attention.

Being dependable is less about talent or character than about whether the things you were asked get noticed and dealt with before they rot. Speed is the visible part. The invisible part is having some system so that nothing sits unseen for a week. People read that as trustworthiness because from outside it looks like exactly the same thing.

Clear your unanswered pile this week, even badly, and reply to the three messages you have been carrying guilt about with one line each. Where you cannot do the thing yet, say when you will. You will feel the weight drop, and so will the people who were waiting.