The word "re-assures" means to comfort or give confidence to someone. Its antonyms, on the other hand, are words that carry opposite meanings. These antonyms include words like unsettle, disconcert, disturb, concern, and worry. When someone is unsettled, they lack confidence and comfort, causing them to have doubts and insecurities. Disconcerting someone makes them feel uneasy, and they become nervous or confused. Disturbing someone means to interfere with their peace of mind, causing them to feel anxious or perturbed. Concerning someone involves making them feel anxious or worried about something. Finally, worrying someone means to cause them to have uneasy feelings and fears, making them feel uncertain or troubled.