A person who can’t be threatened or tempted is unmanageable.

To make someone respect and fear you is the way to make use of them.

You have to care about their interests and hold their secrets. Let them both respect and fear you. If you care about their interests, they will respect you. If you hold their secrets, they will fear you.

When they both respect and fear you, they will be loyal to their duties and honestly provide you with the best service for your money.