Don't meet violence with violence as your first option. But keep it on the table.
Something something “speak softly but carry a big stick.”
Basically, pacifism without the capacity for violence is simply inviting abuse. If you don’t have the capacity for violence, pacifism isn’t a choice; It’s being forced upon you as a tool of oppression. In order to be used effectively, it must be a choice, which requires the threat of violence if pacifism fails.