It is not nearly as out of nowhere as you feared, Signor Ezio, I have heard well of you from Petit. I am not Petit's true father, I am from a mirror dimension, and therefore have very little to no claim on her mother, if such a thing could be done.
My thinking on your interactions with Ronia is very simple: if Petit has decided you are competent and credible enough to hire and introduce to her kin, I have faith in her judgment. The only trouble from me to worry about if things go sour in a bad way. And at that point? I'm not the biggest danger to your self.
My advice would be you can rarely go wrong by starting with old-fashioned chivalry tempered with modern views of her independence. Respect is always preferred by women and if she wishes less courtly overtures, she'll make it known.