(Threatening, but also smug. You're intimidating your ex-girlfriend you deeply want revenge on, and she's terrified. You're winning.)

"Oh, they won’t help you. A fight in the alley. A gunshot? Six guys?"

(Incredibly menacing.)

"What do I want? I want what I had before. What you owe me. I want you to get on your filthy little whore knees, and beg me for forgiveness. I want you to lick my feet, and I want to fuck you on the pavement of this disgusting alley. I want to break your neck."

Not a line as such, but he's murdered pretty brutally, so just whatever impressive screaming and choking sounds you can do.