How Jayel became the proprietor of the Wanton Wench is more or less a hand-waved affair by the local officials. The facts known by 'upstanding' folk are that a fresh-faced young girl by the name of Jayel came into Gatewatch, disappeared, and reappeared the aged and stern woman she is today. The facts known by the night watch are a marked decrease in drug trafficking and battered women appearing on the streets. The fact known by Jayel is that she killed a man with her bare hands, and has never looked back.
One of the standard peices of equipment for an adventurer is a sword. But swords were actually very complicated to manufacture. Therefore, an adventurer who owned a sword might have had it passed down through the generations or might have been rewarded by some influential figure. Or simply looted it from a tomb.