What this statement means is that even if people are speaking bad on your name do not live up to the bad things they said about you. Or in other words prove them wrong.
Answer:
Depending on how you act or interact with people can have a major impact on how others see you and can even change the way you see yourself such as if you were to be hostile when interacting with others you would be defined as a hostile person or if you where kind then you would be defined as kind and outgoing.
Explanation:
Hope you found this helpful :D
(Note: In my opinion I believe nothing defines who you are. You are who you choose to be and you should just be you.)
It was in line after they got off the train