"In a word,be ture to yourself.if you can not put your heart in it,take yourself out of it."翻译

Being true to yourself means:Don't pretend to be something you are not.Don't try to change yourself just to please others.Be honest with and honourable to yourself at all times.
"If you cannot put your heart into it,take yourself out" means:If you don't really want to do something then don't do it.The result of doing something half hearted is - failure to achieve the best you can.