Understand"His bark is worse than his bite."

How to understand this sentence "His bark is worse than his bite."?Thanks for your help!

It describes someone who appears to be meaner or more dangerous than he actually is. For example, perhaps your boss at work yells loudly at the most minor infraction, but he never penalizes you for being late, and is always generous with pay raises and bonuses. His bark is worse than his bite - he sounds mean and difficult, but deep down he is a decent, harmless person.