When you've placed an ad for an independent adoption, you have to be ready to field phone calls from all walks of life. 

Being prepared is the best way to handle this.  You should be ready to tell both the good and the bad about your dog.  Don't be afraid of saying "She eats the arms off our sofa" or "Sometimes, she tears the blinds off the windows when we leave her alone"...after all, you want her to have the best home possible.  You certainly don't want them to be surprised and bring the dog back to you or worse yet...take her to the pound you were trying to keep her out of in the first place!  Right?! 

So, be prepared to share important information like, age, gender, vaccination history, vet history, behavior, etc. and  likes and dislikes.  Does she like riding in the car, or is she terrified the whole trip?  How does she do on a leash? 

If their first question is can he/she have puppies, you want to look elsewhere.  If the caller is obsessed with having a BIG dog, this might be an issue too...do they want the dog as a companion, or do they want a guard dog or status symbol? And will they tire easily when they find out your dane is not a guard dog. ( Danes make poor guard dogs)  If they have no questions, issues or reservations at all. Red Flag...there's a better home a waitin'.