She absorbs and listens
She knows how to treat others
The way to treat someone is with respect and with balance. If you are hogging the conversation, it is hard to be on your side. But this is the kind of girl who knows, whether through nature or through nurture or through both, that people should always have the chance to speak their mind. Rather than seeing this as weakness, people should see this as a sign of respect.
Nobody deserves to be interrupted and nobody deserves to be talked over. She understands and recognizes both of these things, and she walks the walk (even if she doesn't loudly talk the talk).