Well, niece, I hope to see you one day fitted with a
Not till God make men of some other mettle than earth.
Would it not grieve a woman to be overmaster'd with a piece of
valiant dust? to make an account of her life to a clod of wayward
marl? No, uncle, I'll none: Adam's sons are my brethren, and
truly I hold it a sin to match in my kinred.
One of the most attractive of Shakespeare's characters, Beatrice is also one of the most sharp-tongued. Like her male counterpart and eventual husband Benedick, she is "a profess'd tyrant" to the opposite sex, especially him. Here, her uncle Leonato teasingly forecasts her eventually being "fitted" (furnished) with a spouse despite all her resistance. But Beatrice insists, only half jokingly, that it would be absurd and undignified to submit to a mere piece of "valiant dust."
Beatrice's use of "valiant" seems a little strange in this context, especially since she uses "wayward marl" (perverse clay) in parallel with "valiant dust." Today it sounds nobler than she intended. "Valiant" most likely means "sturdy" or "firm" here, a sense still current in Shakespeare's day. A man to Beatrice is merely dust molded into solid form. Besides, she quips, since we're all sons and daughters of Adam, marriage is inherently incestuous.