Short Answer 
In chapter 17 of *The Prince*, Machiavelli argues that a successful leader must balance mercy and cruelty, embracing cruelty when necessary to maintain order and control. He emphasizes the practical benefits of such decisions, stating that hard choices, though perceived as cruel, can lead to greater stability and effectiveness in governance.
Step 1: Understanding Machiavelli’s Claim
Machiavelli asserts that a Prince must demonstrate a balance between being merciful and cruel. He suggests that while a leader should be compassionate when possible, there are times when cruelty might be necessary for maintaining order and control. This duality is critical for a leader to secure their power and enforce their rules effectively.
Step 2: Analyzing the Purpose of the Chapter
The purpose of this chapter is to persuade readers about the necessity of embracing cruelty under certain circumstances. Machiavelli argues that to be an effective ruler, a Prince needs to be willing to make hard decisions that could be perceived as cruel, especially when efficiency and success are at stake. His focus is on the practical outcomes that such decisions can lead to, rather than the morality behind them.
Step 3: Recognizing Machiavelli’s Conviction
Throughout the chapter, Machiavelli emphasizes that a successful Prince must be prepared to act in a cruel manner when required. He presents various examples to illustrate that cruelty can sometimes be a tool for achieving a greater good, like stability and order in the state. Thus, his conviction is that for a Prince to thrive, they must not shy away from making tough choices when the situation calls for it.