Perhaps Bassanio is being selfish by leaving Venice so abruptly.
In Belmont, we learn much about Portia through how she describes her suitors. She makes racist remarks about Morocco saying he has the ‘complexion of a devil,’ however, in Shakespeare’s time this was an acceptable form of humour as Elizabethans hated dark skin. She is cruel but shows that she possesses both intelligence and wit.
Bassanio is the man she wants to marry, but she tries to play down her interest in him after giving herself away to Nerissa; ‘Yes, yes, it was Bassanio!--- as I think so was he called.’
When speaking to Bassanio she is much less assured. She wants to put off the moment where he has to take the test and asks him to ‘pause a day or two Before you hazard, for in choosing wrong I lose your company.’ She is nervous, this might be because she knows which casket Bassanio should choose, she certainly hints at this; ‘ I could teach you how to choose right, but then I am forsworn..’
We know that Portia is very strong willed, but she shows another side to her nature by readily giving herself to Bassanio calling him; ‘her lord, her governor, her king.’ In this way she shows herself to be a much more conventional Elizabethan woman than we first thought.
Portia is cleverer than Bassanio and certainly possesses a greater wit. Bassanio’s speeches before he chooses the casket are comic as they are far too intense. After choosing he praises Portia too much, he is trying too hard to be sincere, maybe indicating that he isn’t, and is more happy about receiving her money.
It is at this time that Portia gives Bassanio a ring telling him that it represents everything she has given to him, and their love. She then goes on to say that ‘when you part from, lose, or give away, Let it presage the ruin of your love, And be my vantage to exclaim on you.’ This is the start of the ring plot, which shows us again that Portia whilst clever, can be cruel.
Portia is unnecessarily harsh on Shylock during the trial scene, she strips him of his religion, although some may argue that he deserved it. Disguised as a lawyer she demands Bassanio’s ring as payment for getting Antonio off the hook. In this way she behaves like Shylock, she tricked Bassanio into swearing a bond he cannot keep and torments him for breaking it. She is using the ring to test her husband, and in this way we see the stronger side of her nature again. Although she is being cruel, we know that she is actually in love with Bassanio. Back in Belmont she tells Bassanio she slept with the lawyer and he gave her the ring, humiliating him in front of his friends. This goes beyond a joke.
However, the fact that Bassanio gave up the ring in the first place tells us something about where his loyalties lie. He puts Antonio before Portia. He does redeem himself slightly though, by telling the truth. He could have just lied and said that he had lost the ring, in this way we see another side to Bassanio as well.
Elsewhere in the play there are hints that friendship is stronger than the vows of marriage. At the first test, Bassanio breaks his marriage vows. Bassanio is tied to Antonio, what will happen now that he is married? Maybe it is selfish of Bassanio to marry Portia when he owes Antonio so much.
Portia suddenly produces a letter saying that Antonio’s ships are safe. There is quite a strong possibility that she was in possession of this letter before the trial as there is no explanation for her just receiving it. In that case, it means that the whole trial was for her own amusement. Again illustrating just how cruel, selfish and dishonest Portia can be.
To some degree, I think that Bassanio and Portia deserve each other. However, considering things just from Bassanio’s point of view I do not think that he deserves to marry Portia. He wasted all of his own money, and then his friends. Before paying back this debt he asked for yet more money. He knew the terms of Shylock’s bond, yet was still happy to see Antonio put his life in danger. I do not believe that Bassanio’s motive for wishing to marry Portia was love, I think he only wanted her for her money. He is no match for her intellectually either. At the first test he broke his marriage vows to her, and appears to value his friendship with Antonio, more than his marriage to her.