My adult daughter lives at home and I want to start charging her rent.
That seems reasonable if she's employed, do you think she'll be upset?
She's employed and she can afford it. I make the rules for the house and I expect her to follow my wishes.
Well, it makes sense to want someone to pay rent if they're of adult age and have the money to do so. It's fine to have a conversation about this with her whenever you're ready.
I don't think she'll resent me, if she's living in my house, I want her to pay rent.
I think it's very reasonable that your daughter pays rent for living in your house. She's working and can contribute to the household expenses. You set the rules and she needs to follow them if she wishes to live there.