What does read his face like a diary mean from romeo and Juliet?

In the context of Romeo and Juliet, the phrase "read his face like a diary" means to be able to understand and interpret someone's feelings and thoughts by observing their facial expressions. It suggests that the person's face is like an open book, revealing their inner emotions and intentions. In this case, the speaker is talking about Romeo's face, implying that they can easily understand what he is feeling and thinking by simply looking at him.