I think this decision to pick the casket that read, “Who chooseth me must give and hazard all he hath” is one of wit and valor. This is definitely the sign of a worthy man. If a suitor is willing to give and risk (hazard) everything for the chance to win the prize that he seeks, he values the prize. This shows that although Bassanio may not have been in “love” with Portia yet, he respected and valued her.
Then he shows his respect and value again as he states:
A gentle scroll! Fair lady by your leave,
I come by note to give and to receive.
Like one of two contending in a prize,
That thinks he hath done well in people's eyes,
Hearing applause and universal shout,
Giddy in spirit, still gazing in doubt
Whether those peals of praise be his or no,
So, thrice fair lady, stand I even so,
As doubtful whether what I see be true,
Until confirmed, signed, ratified by you.
In this beautiful way Bassanio shows that he is so overjoyed over the fact that Portia may now be his wife, but he knows, as a gentleman, that he must have her permission and commitment to do so.