When someone is uncertain or skeptical about something, they may express that they're having their doubts. However, there are numerous other ways to convey this feeling. One might say they're questioning the validity or credibility of a claim, or that they have reservations about a particular situation. They might also express that they're hesitant or skeptical about something, or that they're feeling cautious. Doubts can mean many things to different people, so finding the right words to express them can help clarify what someone is feeling and thinking. Overall, being honest and transparent about one's doubts can help lead to better understanding and decision-making.