When the doctors came they said she had died of heart disease--of the joy that kills.
Firstly, the joy that kills is ironic as joy is never associated with death. The ending also ties back to the first sentence where the author established that she had a heart condition. This was most likely purposeful foreshadowing done by the author.
There would be no powerful will bending hers in that blind persistence with which men and women believe they have a right to impose a private will upon a fellow-creature.
This passage brings forth the question whether she was suffering during her relationship either directly from husband or indirectly from the cultural hardships married women faced especially in the past.
When she abandoned herself a little whispered word escaped her slightly parted lips. She said it over and over under hte breath: "free, free, free!" The vacant stare and the look of terror that had followed it went from her eyes.
Usually when one abandons their will and gives in they become almost lifeless; however, it is the exact opposite in this situation. This begs the question whether she was hoping something would happen to her husband to set her free.