One thing we might learn about love from Shakespeare's play is that there are many differenty levels to the act of love. First, there is Shylock who at first appears to love his daughter. However, when she shames him by running away with a Christian, Shylock's love for Jessica is quickly stripped away, even more so when he discovers that she has taken his money with him. At this point, readers might question which Shylock loves more: his daughter or his money.
Bassanio's love is also rather shallow. He claims love for Antonio, but one wonders if this too is based on money. After all, Antonio lends Bassanio money whenever he asks for it. Bassanio's initial attraction to Portia is also based on money. Whether he overcomes this is not quite clear, as Bassanio's commitment to his love of her comes in question when he gives away the ring that Portia has given him.
Portia's love goes a bit deeper. First, she goes to a lot of trouble to save Antonio, based merely on Bassanio's friendship for Antonio. Then Portia forgives Bassanio's transgression over the ring, despite the fact that he failed her test of his love.
However, the deepest love portrayed might be that of Portia's father, who even in death made arrangements to find the most worthy of suitors for his daughter. Whether the king's plan succeeded or failed is immaterial. His love for his daughter was so important, he created a plan that he thought would work.