How does Bassanio win Portia's heart in Shakespeare's The Merchant Of Venice?
The play does not present any specific reason as to why Portia fell in love with Bassanio, but we can gauge from what the characters say that she had a particular affection for him. Bassanio, in Act 1, scene 1, for example, has this to say about her as far as her feelings go, when he approaches Antonio for a loan:
In Belmont is a lady richly left;...
...sometimes from her eyes
I did receive fair speechless messages:
Her name is Portia,...
He states that he was encouraged by the looks Portia gave him. She gave him a clear indication that she liked him by looking at him in an affectionate and appreciative manner.
Later, in scene 2, Portia and Nerissa, her hand-maiden, also make positive references to Bassanio:
Do you not remember, lady, in your father's time, a
Venetian, a scholar and a soldier, that came hither
in company of the Marquis of Montferrat?
Yes, yes, it was Bassanio; as I think, he was so called.
True, madam: he, of all the men that ever my foolish
eyes looked upon, was the best deserving a fair lady.
I remember him well, and I remember him worthy of
Portia supports Nerissa's positive appraisal of Bassanio in that he was the most deserving of a fair lady, thus confirming her fondness for him.
When Bassanio arrives at Belmont to try his hand at choosing the right casket, her statements to him during their conversation serve as an affirmation of her love. She says, in part, the following in Act 3, scene 2:
I pray you, tarry: pause a day or two
Before you hazard; for, in choosing wrong,
I lose your company: therefore forbear awhile.
There's something tells me, but it is not love,
I would not lose you; and you know yourself,
Hate counsels not in such a quality.
Portia beseeches Bassanio that he should not rush into choosing since she does not want to lose his company too quickly if he should make the wrong choice. She does not want to lose him so quickly. She further expresses her love for him by saying that she could give him guidance about which casket to choose, but that she had made an oath and would then have to relinquish everything since her father's will forbids her from providing a suitor any help.
She also confirms that half of what is hers is also his, but that it would mean nothing if he should choose wrong. Portia's anxiety is clear. She says that fate should suffer the consequences of Bassanio making a wrong choice, not her. She acknowledges that she is speaking too much but that it is just an attempt to retain Bassanio's company before he makes a choice. These are clearly the expressions of one in love.
As Bassanio prepares to make his choice, Portia asks him to confess his love for her since he has declared that he is in torment, for he fears that he might not enjoy her love. He then states that his entire confession is the sum of his love. Portia then expresses the depth of her love just before Bassanio chooses a casket by saying:
Live thou, I live: with much, much more dismay
I view the fight than thou that makest the fray.
She compares Bassanio to Hercules who is about to enter battle and states that she will suffer more in watching the battle than he who is actually involved in the fight. The exaggeration emphasizes her passion for Bassanio.
When Bassanio chooses the right casket, Portia is obviously happy and she expresses her joy to surrender to Bassanio's guidance and teaching. She states, towards the end of her speech:
Myself and what is mine to you and yours
Is now converted: but now I was the lord
Of this fair mansion, master of my servants,
Queen o'er myself: and even now, but now,
This house, these servants and this same myself
Are yours, my lord:
It is clear that Portia loves Bassanio not for what he has done, but for the fact that he is who he is. He did not have to do anything in particular to win her affection. She probably loved him from the moment she first laid eyes on him. One can assume that Bassanio, too, felt the same about her.