A special meaning of "would have"?

1. Your lord father was as true a man as the realm has ever known, but I stood by and let them slay him. I said nothing, did nothing... and yet, when Joffrey would have slain me, you spoke up. Lady, I have never been a hero, no Ryam Redwyne or Barristan the Bold..."

2. Jon could feel himself turning red again. “She spoke for me when Rattleshirt would have killed me. I would not dishonor her.”

Hi, dear teachers. I was told by some native speakers that the "would have slain" in the first sentence means "wanted to slay me, was intending to slay me". So I guess the "would have killed" in the second sentence also means "wanted to kill me".

Is my understanding correct?

Thank you.