I don't want my wife to book a hotel by herself for a night away
Why don't you want her to do that?
She was talking to an old high school friend about doing it and I don't trust her.
I can understand why you are worried. It's not cool not to trust your wife to be alone at a hotel, though, if she hasn't done anything to warrant distrust.
She was too eager for this trip, I think.
You either need to trust your wife or don't. Because what you're doing will only fill your marriage with distrust.