My wilds get pretty savage during courtship. I could always tell when they were feeling ready as the male and female would have a full-on flare and fight session before commencing.
My rutilans female is highly aggressive towards the male when she is ready, and they will nip and chase each other around for a few hours pre-spawning.
However, I have never had a male seriously harm or kill a female, which I know can be the case with splendens.
I find that with bettas, the violence shown during the courtship process seems to be a test by both fish to see if their partner is the best possible candidate for spawning.