The arrow flies true when your heart and mind are in perfect alignment. Have you ever observed how you sometimes get things easily and sometimes not? It is the nature of life, yes, but it is also when the heart and the mind want the same thing.
Sometimes only the heart wants but the mind says it is not good for you and sometimes we logically rationally want something but the heart is busy looking at something else. Sometimes we truly want something but are assailed with doubt about our worthiness or whether we deserve it, did we work hard enough for it, does someone need it more. There is plenty that can be at cross purposes inside us.
Have an intention, set your goal and then work through all the doubt that emerges and then like an arrow, fly true to your purpose <3.