Bassanio picking a casket

Portia clearly wants to marry Bassanio. Yes, we realize this is an unfortunate choice given that Bassanio wants Portia's money and seems to value his bromance with Antonio more than his relationship with her. When Bassanio shows up to try his luck at the casket lottery, Portia has her band of personal musicians play a little tune that helps Bassanio make the right choice