To show a completely different mental state without being seen through by others, you can consider the following aspects: 1. **Emotional management**: First, learn to control your emotions. You can stabilize your emotions through deep breathing, relaxation training or short meditation, so that you can appear more calm and composed on the outside. 2. **Non-verbal expression**: Pay attention to your body language and facial expressions. Keeping a smile, a relaxed posture, and friendly eye contact can help you create a positive atmosphere. 3. **Tone and speaking style**: Change your tone and conversation style. Use positive and optimistic language and tone in communication, which can effectively convey the mental state you want to show. 4. **Situational adaptation**: Adjust your performance according to different environments and occasions, and adapt to the emotions and atmosphere of the people around you, which can make you appear more natural. 5. **Small details**: Pay attention to the presentation of external images such as clothing and dressing. Appropriate dressing can make you feel at ease in different states. 6. **Practice and drill**: Strengthen psychological quality through practice. Practicing to show different emotions in front of the mirror can help you be more confident in real situations. 7. **Set goals**: Identify the mental states you want to project and gradually incorporate these traits into your daily life until they become natural habits. 8. **Stay true to yourself**: While it is important to project different mental states, avoid completely masking your true self. Showing your true emotions and states, when appropriate, can make relationships more authentic and deeper. In these ways, you can change your external performance to a certain extent without letting others see through your true emotions.