@Inna22 You can't ask for feedback and then get all huffy when you get it. It sounds like the guest took your request literally and gave you an honest comment. That doesn't mean it's some kind of demand that you spend $10K to replace your air conditioner - it's just one person's opinion about a detail that might have affected her stay.
Seems to me that your review should be based on how she was as a guest (you said yourself there were no problems), not on what kind of reciprocal review you imagine you'll get. Future hosts who care what kind of reviews she leaves will still be able to cross-reference, so there's no need for a pre-emptive strike.