This long scene brings the casket story to its climax with Bassanio's choice. It begins with Portia's speech begging Bassanio to delay in making his choice of caskets, "for in choosing wrong / I lose your company." Essentially, this speech is evidence for us of Portia's love for Bassanio, and the charm of her speech lies in the fact that Portia cannot openly admit her love. She continues, and her attempts to verbally circumvent stating outright her feelings for Bassanio lead her to utter absolute nonsense. She declares: "One half of me is yours, the other half yours — / Mine own I would say; but if mine, then yours, / And so all yours!" This makes absolutely no sense at all; she is nearly giving in to her urge to tell Bassanio directly of her love for him.
Bassanio is obviously relieved to see that his love is returned. He speaks of feeling as though he were strained tautly on the rack. This admission, in turn, relieves Portia's anxiety somewhat, and her old spirit of jesting returns and she wittily picks up on Bassanio's choice of metaphor and teases him. This witty wordplay has the effect of delaying the choice of caskets and further allowing Portia to relax and display her spirit and sense of wit. We are never allowed to forget her intelligence because this element will be the key ingredient in the play's climactic scene. Bassanio moves to the caskets, and Portia begins a lovely speech, built around the notion of sacrifice. Her phrase "I stand for sacrifice" is particularly apt. Twice, we have watched Portia prepare to become a sort of sacrificial victim, as it were, to unwanted suitors. She has not complained, but we now see that her role in this casket contest contains special intensity. Should Bassanio choose wrongly, she will literally be a sacrifice to a later, unloved husband, as well as being forever a victim of unfulfilled love.
The central idea in the song that is used as background music while Bassanio is making his choice of caskets focuses on the word "fancy." Fancy, for Elizabethans, carried the meaning of whimsical affection. Bassanio picks up on this idea and elaborates on it when he meditates on the way in which "outward shows" mislead or deceive the observer. He extends this perception to law, religion, military honor, and physical beauty.
