What does "silence" mean?

Depends on the question what 'silence' indicates. It really can mean anything depending on the cirstances. It can be an affirmative 'yes', or a 'no'. Ususally it means the person just doesn't want to speak the truth aloud. But it can also mean that they simply don't know the answer. However if you were asking her if she was reconsidering the relationship and received no response, then unfortunately, I would hazzard a guess that's a negative.