Love spells are a horrible idea. Who are you to try to make someone feel something for you that they don't feel with to begin with?
It's not really ethical in my eyes. You're forcing something on someone they do not want nor do they feel in the first place.
Wouldn't you feel better about yourself loving someone who you know loves you and isn't a fictitious love you've forced upon them?
If you're going to do a love spell, do a revealing spell. Do a spell that makes TRUE feelings come out, not force it.
You have to understand that it's not ethical to do things against people's freewill. It's not fair to them, and you're only cheating yourself.
Life is hard and we want a magic wand to fix everything, but it just doesn't work out like that. People have to feel how they truly feel. You have to be true to yourself and let others be true to themselves as well.