It's difficult to guess his feelings from his actions.

It's difficult to understand his feelings.

I couldn't understand his actions.

He started to act immediately.

We should always remember the power of Kannon in difficult times.

He expressed his complaints on the internet.

After watching that movie, he felt sick.

He is an expert in ethology, and his research is highly regarded worldwide.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.