Its about confidence (of a young girl). When she says you feel safe inside your room and are free to dream. This means that we should find the confident to be ourselves and dream further than when we are alone.
It is also saying that if you are having a bad day a better one will follow.
She is also saying that we should trust the voice within. We are our own best friend and have known ourself better than anyone else knows us. We should be able to trust ourself.