Her pride is best characterized in those lines, the "Didn´t come to this world to be no slave" is a direct exemplification of her pride and her capability to see the great scheme of things and how she should do with her life what she felt she needed to do, and "didn´t stay one either" part shows the pride of her to stand up and face the situation she was in and change it. She knew her value and what she was worth and was sure of that.
A because besides the US felt close to the British since there ancestors and language, when Germany swept across Belgium it made the Americans feel sympathetic towards the allied powers.
