The abstract noun "understanding" can be expressed with the verb "understand." Alternate translation: "But foolish people do not understand" (See: [[rc://en/ta/man/jit/figs-abstractnouns]])
Since a wild donkey can never give birth to a man, this means that foolish people will never get understanding. Alternate translation: "only if a wild donkey could give birth to a man could foolish people get understanding" or "it is as impossible for a foolish person to get understanding as it is for a donkey to give birth to a man" (See: [[rc://en/ta/man/jit/figs-irony]])