Why is the woman powerful?

The ending chapter with the inscription on her fathers tombstone which read:‘To strive, to seek, to find, and not to yield’

here is the line which mary realizes this: And in all this gaiety of a new-born world only she was to have no part. Henceforward she was to stand alone, to fight the dreary battle of life unaided. ‘And women live long,’ came the ironical thought: ‘yes—we live long!’