what does Amanda know about "...what becomes of unmarried women who aren't prepared to occupy a position"?

Amanda is not concerned about love for Laura. She only knows that Laura must get married to be socially acceptable and to find someone to take the burden of Laura off of her.

I know so well what becomes of unmarried woman who aren't prepared to occupy a position. I've seen such pitiful cases in the South - barely tolerated spinsters living upon the grudging patronage of sister's husband or brother's wife! - stuck away in some little mousetrap of a room - encouraged by one in-law to visit another - little birdlike women without any nest - eating the crust of humility all their life! act 2