Somebody’s bark is worse than their bite
Definition 1 of 1
Pro Tip 1/3False Intimidation
The phrase often refers to people who seem tough but aren't. It's used to reassure that fear is unnecessary. 
The new coach shouts a lot, but his bark is worse than his bite.
Pro Tip 2/3Misleading Appearance
Sometimes appearance or first impressions could be deceptive. This phrase invites looking beyond them. 
She may seem unfriendly at first, but her bark is worse than her bite.
Pro Tip 3/3Not Literal
This is a metaphorical phrase. It's not about real barking and biting, but about a person's behavior. 
Our boss can be loud, but don't worry, his bark is worse than his bite.