that medicine is not something the other class are aware of he mention it was a secret of his line of work he is mainly and assassin is not just to be hidden from the public but from the other classes and organisations as well and following the moral line of the paladin families she is only alive because they haven't prove she is a bastard which it was suppose to be his job to find out but now he won't do it, look at the paladin arrogance and self importance they will rather kill her and make it like she never existed then bring shame to there line allowing a bastard like her become a paladin with a shady medicine, they are so proud of there line that they knowing she was made and not born will still be a stain in there line.