Yup, I'm a professional dominatrix and having these open conversations is a must. If done correctly, it invites deeper intimacy and helps the relationship grow - it doesn't drive people away. The only reason honesty would drive someone away, is exactly the reason you should be honest - so they can have informed consent about what's taking place and say no if they want to. If someone isn't allowed to say "no" in the first place, then whether they say yes is irrelevant. Can't consent if you can't dissent.