I am determined to be cheerful and happy in whatever situation I may find myself. For I have learned that the greater part of our misery or unhappiness is determined not by our circumstance but by our disposition.

The saying expresses a stoic, self-governing ethic: happiness is treated less as a product of external conditions than as a choice of attitude. It distinguishes “circumstance” (what happens to us) from “disposition” (how we meet it), arguing that emotional suffering is often amplified—or alleviated—by one’s habitual outlook. In quotation culture, the line is frequently used to encourage resilience and gratitude, implying that inner discipline can preserve cheerfulness even amid hardship. However, because the attribution to Martha Washington is doubtful in the historical record, the quote’s significance today is largely proverbial rather than securely tied to her documented voice or a specific episode in her life.