The corner store owner who let you pay him back the next day trusted you before you’d earned it.

Trust extended before it is earned is how every reputation actually begins. A man behind a counter had no reason to let a kid walk out with something unpaid for, and he did, which means the first entry in your record of being reliable was somebody else’s risk. Most people get a start like that from somebody who had no obligation to give it.

Honor the one you were given by being exactly as reliable as he guessed. Then extend a small piece of trust yourself to somebody who has not earned it yet.