The paragraph suggests that a woman who is intelligent and cunning can always find a way to deflect blame and make her husband appear to be in the wrong, even if the accusation is baseless.
What does the paragraph show ?
The phrase "she knows enough to prove the bird is crazy" implies that she is skilled at manipulating situations and using misdirection to discredit any negative rumors about her.
The reference to "the little bird" could be a metaphor for gossip or rumors that are spreading around, and the wife's ability to "get her maid to witness she's a daisy" suggests that she is able to control the narrative and ensure that her reputation remains intact.