That's how* she got sick
Yeah, I was confused on whether that was her mom too.
What I thought happened was that one crazy dude lowered that courtesan's price by deflowering and impregnating her, but then never married her and so she had to then work as an average prostitute since she was no longer considered 'pure'. Plus she gave birth to Mao Mao and apparently that's about as low as you can go to no longer be considered a high class courtesan.
That's what makes the most sense. Cuz her mum couldn't have always been a virgin--otherwise Mao Mao wouldn't exist
╮(￣▽￣)╭
In fact you can have a child without doing sex and staying as a virgin but the means are not enough in her world since it's back in time
It can't be her mom, her mom was someone who was worth a lot because she was a virgin so the woman with syphilis can't be her mom because it is said that at the time when she was a courtisan, she had to take in lots of customers, that's she got sick