How does the principle of sufficient reason apply to Leibniz’s truths of fact?

In the philosophy of Gottfried Wilhelm Leibniz, the principle of sufficient reason serves as the foundational explanation for the existence and nature of contingent things—what he termed "truths of fact."12

While "truths of reason" are necessary propositions whose denial would result in a contradiction, "truths of fact" are contingent; they hold true in the actual world but could conceivably not exist. Because these facts are not logically necessary, they require an external account for their existence.12

Leibniz asserted that nothing is the case without a sufficient reason to explain why it is so rather than otherwise. For truths of fact, this ultimate sufficient reason is found in the free choice of God. By selecting the actual world from among all possible worlds, God provides the necessary justification for the existence of contingent entities, such as monads, despite their inherent contingency.21