As for her marrying a person of some other religion, that is not allowed in Islam, now the enforcing bit, that depends on how liberal I am
TBH, i dont think my parents would like that much, but as for ME, my duty is to ensure she knows the principle, if she decides to go against it, thats her will and according to the teachings of Islam, I would not be held accountable for her personal deeds, my duty is to make sure she knows what is required for her to do, if she chooses to go against the religion, its her choice.
But the problem does not end there, once she does that, I will receive calls perhaps taunts too from neighbours, family members possibly or simply people talking crap behind my back, " Do u know what his sister did?", I might even have problems marrying myself, when people get to know, so that would be a social reaction, how I react to it, will be my choice, nothing to do with the religion