To reassure someone means to comfort them and help them feel less worried or scared by offering kind words or reminding them of facts that should make them feel better. When your friend is nervous before a big presentation and you say, “You've practiced so much, you're going to do great,” you're reassuring them.

Parents often reassure children during thunderstorms by explaining that they're safe inside. A teacher might reassure a student who failed a test by reminding them that one bad grade doesn't define their abilities and that they can improve with practice. A doctor reassures a patient by explaining that their symptoms are normal and nothing to worry about.

Good reassurance addresses the specific fear with reasons or evidence. If your little brother is afraid of the dark, simply saying “there's nothing to be scared of” is less reassuring than turning on a nightlight and explaining that his eyes will adjust, or that you're right in the next room if he needs you.

When you feel reassured, that anxious knot in your stomach loosens. You might still face the same challenge, but you feel calmer and more confident about handling it.