I really agree with this quote and I really identify with it. This is just how I feel about my happiness and the meaning of happiness in general. What she means by this quote is that she is determined to be happy and positive no matter what her situation, because ultimately happiness is all about attitude. in order to be truly "happy" you have to train your mind to be more positive about life
What Buddha means by this quote is that happiness does not have material value and it will not run out. If you have happiness within yourself you should share that happiness with other people. It will never run out.