Frailty, thy name is woman
A well-known Shakespearean proverb used to express the idea that women are weak or fickle. Often quoted in literary or dramatic contexts.
He lamented, "Frailty, thy name is woman."
From Shakespeare's Hamlet, Act 1, Scene 2: 'Frailty, thy name is woman!' The Japanese translation is a well-known rendering of the line.