Thanks, I'll be sure tell my parents (mom used to be dad's secretary) that their 35y relationship will end in failure.
If someone else had applied for the position as your father's secretary and had been refused, they could have complained about it by pointing to the conflict of interest.
If you want to avoid the negative consequences of mixing work and romance, you'd better not only focus on the best-case result, but also keep the worst case in mind and accordingly tread carefully.
It's still incredibly inappropriate to ask someone out when you can fire her. How do you know she really wants to say yes?