The correct answer is:
One must know the process of hiring servants.
In the excerpt, especially here:
<em> "when you see the servant thinking more of his own interests than of yours, and seeking inwardly his own profit in everything, such a man will never make a good servant, nor will you ever be able to trust him; because he who has the state of another in his hands ought never to think of himself, but always of his prince, and never pay any attention to matters in which the prince is not concerned."</em>
They describe how to analyze a servant, how to know when they are going to priorize you, and if the servant does not checks for all of this characteristics is better not to hire him.
Just because references are an option im gonna say those,
