Eyes and Judgement
When Beatrice-Joanna first meets Alsemero, she cautions him against trusting his passions when he compliments her appearance. She tells him, "Our eyes are sentinels unto our judgments / And should give certain judgment what they see / But they are rash sometimes, and tell us wonders / Of common things" (1.1). Here, she uses a metaphor to compare eyes to sentinels – soldiers who stand guard – to one's judgment, suggesting that eyes aid proper judgment. But she qualifies her statement by also saying that eyes can deceive judgment. Beatrice-Joanna is unknowingly commenting about her own duplicitous ways.
Diamonds
After Beatrice-Joanna decides that she loves Alsemero, she is convinced she sees him with rational, correct judgment. She says, "A true deserver like a diamond sparkles, / In darkness you may see him, that’s in absence, / Which is the greatest darkness falls on love" (2.1). Here, Beatrice-Joanna uses a simile to compare a great, deserving lover to a diamond that sparkles even in darkness. Diamonds become an important symbol of love and transactions throughout the play.
Enemies
When Tomazo explains his concern to Alonzo about Beatrice-Joanna's lack of affection for him, Alonzo is offended. He tells his brother, "I should depart / An enemy, a dangerous, deadly one / To any but thyself, that should but think / She knew the meaning of inconstancy" (2.1). Here, Alonzo uses a metaphor to compare a dangerous enemy to anyone who would accuse Beatrice-Joanna of disloyalty. This conversation foreshadows Beatrice's actual disloyalty and seals Alonzo's death sentence.
DeFlores's Argument
In likely the most famous speech from the play, DeFlores reminds Beatrice-Joanna that the act he committed also implicates her in a unique way. He tells her, "Y’are the deed’s creature; by that name / You lost your first condition, and I challenge you, / As peace and innocency has turn’d you out, and made you one with me" (3.4). Here, DeFlores uses a metaphor to compare Beatrice-Joanna both to a "creature" and his moral twin, suggesting that they are now linked forever.
Cursed Womb
When Beatrice-Joanna agrees to sleep with DeFlores, she resigns herself to her sinful fate and asks, "Was my creation in the womb so curs’d, / It must engender with a viper first?" (3.4). Here, Beatrice-Joanna uses a metaphor to compare DeFlores to a "viper," whom she must have sex with because her own creation, she assumes, was cursed. Of course, Beatrice-Joanna uses this excuse to deflect from the fact that she is responsible for her own actions.