system
Given the following post, respond as if you're commenting on Reddit:
human
[Kill Bill] Why doesn't The Bride use her Hattori Hanzo sword to kill Vernita Green?

After she awakens from her coma, Beatrix goes to Okinawa with the express purpose of stirring Hanzo out of retirement to make her a sword in which to exact her revenge against the Deadly Vipers. She uses the sword to great effect against O-Ren, Sofie and the Crazy 88's, but then mysteriously leaves it behind when confronting Vernita, attacking her armed only with a small knife. Why not use the killing machine you spent a month waiting to be made for the purpose you got it made for?
gpt
The bride intends to face each of her would-be assassins with the same weapon they themselves are predisposed to using.  

Notice that when she visits Vernita, not only does she instantly throw the first punch after the door opens, but she only shows up with a knife holstered.  Later she comments that Bill said she was the best women he had ever seen with an edged weapon.  As an assassin a knife is vastly more practical than a sword hence why Vernita was good with knives and Beatrix only confronted her with a knife.  The challenge to a duel at night was only after the daughter showed up and made finishing the fight in the house impractical and dishonorable.  Remember she had no wish to murder her in front of her child.

Everyone else she fought or attempted to fight with a sword.  O-Ren obviously.  Bud she knew had a Hanzo sword so she tried with him but got shot because she underestimated him.  Ellie we see was not only a student of Pai Mei but knew how to use a sword so Beatrix likely meant to confront her with a sword but that went down at Buds trailer after he died.  And we see that while she showed up to Bills house with a gun, she also had her sword on her back and in the end they both basically agreed to end it all with a sword fight.