Once she became a Master of Arms, sister Seraphine agreed on an offer to become a provost, and fully embraced the oath.
Especially the part about keeping peace.
In the first weeks, as soon as she would witness a tavern brawl, she would throw herself into the fray and would not stop until all people involved were on the ground and had understood that trying to get up again without her leave was the wrong option.
Quickly, the mere mention of her name would nip a tussle in the bud.