I first encountered the bolded quote on p 80, Philosophy: A Complete Introduction (2012) by Prof Sharon Kaye (MA PhD in Philosophy, U. Toronto), part of Chapter 6 on Thomas Hobbes, Rousseau, free will, determinism, and compatbilism.
[ Reddit :] I do not at all believe in human freedom in the philosophical sense. Everybody acts not only under external compulsion but also in accordance with inner necessity. Schopenhauer's saying, "A man can do what he [wants]1, but not [want]2 what he [wants]3," has been a very real inspiration to me since my youth; it has been a continual consolation in the face of life's hardships, my own and others', and an unfailing well-spring of tolerance.
I conjecture the 3 wants above mean different desires: 1 and 2 mean primitive superficial urges or John Stuart Mill's phrase 'lower pleasures' (eg:chocolate, guilty pleasures, etc...); but 3 means John Stuart Mill's phrase 'higher pleasures' or second-order virtuous aretes. Did I neglect anything?