Mark was very friendly and English is fluent. His reply soon. He enthusiastically gave us help: guiding us, reminding us attention, and even borrowed us a Chinese travel guide! When we arrived he was already in the apartment downstairs waiting for us. This apartment is in the center of Prague, within walking we can visit the main attractions. This apartment is very bright, spacious and full of style. Mark's colorful keys are really cute by the way ;) . Before we left, he offered us a room to store luggage.
After all, this apartment is the private residence, not a hotel. If you are extremely demanding cleanliness, like me, then I suggest staying in a hotel.