What is the one thing Amanda begs of Tom?

Amanda begs Tom notto leave until his sister is married and has a home of her own.... until someone else can take care of her.

AMANDA: I mean that as soon as Laura has got somebody to take care of her, married, a home of her own, independent ?- why, then you'll be free to go wherever you please, on land, on sea, whichever way the wind blows you! But until that time you've got to look out for your sister. I don't say me because I'm old and don't matter - I say for your sister because she's young and dependent.