I love Shakespeare!!!
And what is music then? Then music is
Even as the flourish when true subjects bow
To a new-crowned monarch. ....
I stand for sacrifice; The rest aloof are the Dardanian wives,
With bleared visages come forth to view
The issue of th'exploit. Go, Hercules.
Live thou, I live.
-Portia
it is pretty much saying that Portia, giving a speech to Bassanio before he chooses his casket. She gives him music in order to suggest that her rhymes are hinting at the lead casket.
I am here to be sacrificed- she as an individual is destroyed to save her father's estate. Here future is a function of the value of the estate. It remains to be seen whether is willing to be sacrificed or not.
She compares Bassanio to Hercules- who will save her. This is a complimetn however she references him as a fortune hunter by mentioning this. By saving Troy, Hercules got not the maiden but the horses of her father.