You have been asked a question - take it at face value! So ask for what you'd like - a glass of sparkling water, a cup of tea or a glass of champagne.
Their feelings about it, and their response, is their concern. You've been offered something and I think it is reasonable to take that offer as sincere. To me it sounds like in this case she would have liked to bring you something.
There is quite a lovely expression that someone once said to me - 'It takes generosity to receive'.