James doesn't speak very clearly.
Compare these two sentences:
1. It is difficult to understand him.
2. He is difficult to understand.
You can use the same structures with many different words like:
- Easy, nice, safe, cheap, dangerous, exciting, impossible etc.
Example:
1. Do you think it's safe to drink this water?
2. Do you think this water is safe to drink?
You can say 'it's nice of somebody to do something':
- It was nice of you to take me to the airport.
You can use adjective + to... to say how somebody reacts to something:
- I'm sorry to hear that your mother isn't well.