On the surface, Nostromo's line is something of a lie: what he was afraid of losing
was the silver, if Giorgio forbade him the island. But I hear an allegorical
level, in which "hope of you" means hope in the utopian socialist future.
I.e., to achieve that future the People must engage themselves to lawful society
and continue their unlawful pilfering of wealth. If deprived of that, they would
lose their "hope." Continuing on that level, Giselle's retort dismisses
the need for wealth, replacing it with "soul."