If you want to be a fine person, act in a fine way, even if inwardly you’re not so refined. After a while, your inside changes and you become good. For example, if you are polite to people, after a while you become inwardly polite. That’s why it’s important to speak politely and to avoid gruff talk.
There’s no question that your intrinsic character changes as a result of your external behavior.
~ R’ Avigdor Miller zt”l