Sometimes spells don’t work because we desire people for the wrong reasons. Simply put: You can’t make a person fall in love with you. As stated above, the feelings in the relationship must be mutual. If they are not, then the magic will fall flat.
Additionally, magic only works if you are putting yourself out there. As in non-magical love, if you're sitting at home and not interacting with others, you're not super likely to find your true love. You get what you give.