Doing some follow-up reading after the splendid Borgia series.. here’s the famous passage about love or fear as a ruling tactic.

Kind eyes... practical thinking..
First, on human nature:
Because this is to be asserted in general of men, that they are ungrateful, fickle, false, cowardly, covetous, and as long as you succeed they are yours entirely; they will offer you their blood, property, life, and children, as is said above, when the need is far distant; but when it approaches they turn against you.
And even if love and fear is the best authority – love has to go first:
Upon this a question arises: whether it be better to be loved than feared or feared than loved? It may be answered that one should wish to be both, but, because it is difficult to unite them in one person, it is much safer to be feared than loved, when, of the two, either must be dispensed with.
But – as the 15th century Italy was a lump of independent cities in constant battle – this context shaped his thinking. A prolonged peaceful period of time for a government was never experienced or even thought possible.
Same goes for his experience of human nature – it was a somewhat tilted society he grew up and worked in. All he ever saw was permanent games of power and wealth – even the church was about to split religion and politics apart, as the absolutes of faith often proved impractical in governing the papal state.