This (Dorte) is the name of one of my best friends. The sound is most similar to what could be explained in English as DOOR-tuh (like in 'a door' or 'adore'). Her parents were originally going to call her Dorde (pronounced the same way) but I'm glad she ended up as Dorte which is much prettier to me!
Three girls in my earlier school class were called Dorthe or Dorte, and also I had a teacher with this name. Today not many are named Dorthe though. I don't think it's anything special. But I really like that it means "Gift of God".