Dear Anna,
We are writing to express our appreciation for your hospitality. You have provided a very nice place to make our stay in Barcelona most enjoyable. The location, the facilities, the view, everything is just right. We loved it.
Also, many thanks for your help in making all the bookings for us, it saved us a lot of trouble. If everything goes well, we are looking forward to staying in your place sometime in the future again.
Best regards,
Kennis