I'm always afraid of saying the wrong thing when talking to others. What should I do if my eyes are not firm occasionally?

That's because you are not confident. You are afraid of saying the wrong thing and offending others. In fact, everyone has such a mentality. But, don't do this. As long as what you say doesn't touch other people's interests, don't be afraid of other people's opinions from their point of view. Besides, people should not care too much about other people's feelings. Think about yourself first. If you have something to say, just say it. It's uncomfortable to hold it in your heart.