Your name is who you are

"Betony Rue." said the Hag in summons. The little shuddering girl in the corner didn't respond.
"Betony Rue!" said the Hag again. The weak little girl sniffeled in confusion. Her name wasn't Betony Rue. It was - CRACK!
The Hag the girl over the head. Blood started to mat her hair and her right ear seemed to have gone deaf from the blow. "You will come when I call!" screamed the witch Fey. "Understand that."
"But my name is -" CRACK!
The Hag hit her again. It wasn't that hard compared to what the Hag was able to do, but the little girl was still too weak to be taught with the full force of her blows. The Hag, such a good teacher was she, knew that and would work up to that. She knew how much force to use.
"Never contradict me. Now come Betony Rue!"
The weak little girl stayed curled up in a ball weeping.
CRACK!

It would take many more lessons but the weak little girl would eventually come when the Hag called Betony Rue, even though her name was - CRACK!

The the siren thought she was being clever. She had noticed Betony Rue's penchant for addressing others by they're last names. She had asked for Betony's and had been told Betony Rue didn't have a last as far as anyone (or Betony for that matter) knew of.
So she had taken to calling her the Jasons woman. Jason, a name derived from the Greek "to heal". The siren thought it was amusing beyond belief given the pain normally experinced during her operations.
As such things do sometimes, it caught on. No one ever called Betony that to her face, but it became a title of a sort. She was the one freeholders went to to mend injuries. She was the healer woman, the Jasons woman.
Then some scribe made the mistake of thinking it really was her last name and put it down in the Court records. He realised his mistake when Betony left for California and another Jasons woman was appointed. The letter of introduction to Sacramento was inaccurate in regards to Betony's name, calling her Miss Betony Rue Jasons.
Betony Rue found the entire thing unimportant and didn't bother to correct the mistake when she arrived.