I think you can tell the difference if you are really feeling something for someone for real or not. I was a victim once, and I believe under a very 'controlling' one. You can tell especially if you never had any interest in them to begin with and found them in no way attractive and then you suddenly do out of nowhere. When it happened to me, I wasn't attracted to the guy at all and a week later he looked like a completely different person. It was like an illusion to see what I want to see :/ If you find yourself suddenly obsessing over them out of nowhere, unable to sleep cuz you are thinking of them, dreaming of them, not tending to your responsibilities because of it, I would say a spell, and a really bad, controlling one. If I had been into magic back then, I think I would have realized what was happening. I'm grateful for it now to know that magic is real and at this point in my life I love using it myself, even for love situations, but would never torture someone to the extent that I was. Although I'm not against what anyone else chooses to do.
I think anyone already into magic has an advantage over those who aren't, to be able to tell the difference. I think they are great if done in a more friendly way. But in my case, not so much.
Many names, One Spirit.
Many paths, One Truth.
Many thoughts, One Mind.