Final answer:
The irony in Macduff's remark that the news is not suitable for a woman lies in the stark contrast to Lady Macbeth's demonstrated strength and involvement in violence, defying gender norms and highlighting a thematic element within Shakespeare's play.
Step-by-step explanation:
The remark by Macduff that the news is unsuitable for "a woman's ear" is ironic because Lady Macbeth, the woman to whom he is referring, has been a central figure in inciting and plotting the brutal violence that precipitated this news. This irony stems from traditional gender expectations, where women were thought to be too delicate or gentle to handle the gruesome details of violence and murder, a notion Lady Macbeth defies throughout the play.
In his statement, "The repetition, in a woman's ear, Would murder as it fell," Macduff expresses a sentiment that is at odds with Lady Macbeth's previous actions and her proven psychological and emotional strength, particularly her earlier wish in the play that the spirits would "unsex" her and fill her with cruelty. This contradiction emphasizes the gender norms of the era, while simultaneously highlighting Lady Macbeth's unique and powerful role in the narrative.
The portrayal of Lady Macbeth juxtaposed with Macduff's conceptions creates a powerful thematic discussion about the complexities of gender and the capabilities of women, accentuating the deeper societal commentary woven throughout Shakespeare's Macbeth.