Lady Russell "received [the alliance between Anne and Wentworth] as a most unfortunate one." Austen goes on to describe all the reasons why (from Lady Russell's perspective) an Anne Elliot of Kelynch Hall should not involve herself with a man like CW, with such an uncertain future.

Included in these reasons: Anne Elliot, so young; known to so few, to be snatched off by a stranger without alliance or fortune; or rather sunk by him into a state of most wearing, anxious, youth-killing dependence!

Yet, "youth-killing dependence" ends up being her fate regardless, doesn't it? In fact, only three paragraphis later, Austen tells us that: Her attachment and regrets had, for a long time, clouded every enjoyment of youth, and an early loss of bloom and spirits had been their lasting effect.