Mental confusion, or an inability to think about anything other than the suspected beloved is perhaps the better predictor, but even that is hardly certain. Old age and multi-tasking are surer paths to mental confusion and obsessing with another person may well be caused by love, but may equally well be caused by schizophrenia.
No, the only sure indicator that you are experiencing the King of Emotions is that your feelings towards your beloved are exactly described by the lyrics of popular songs.
This is the only foolproof test of love. If you suspect you are in love, turn on the radio in your car. You probably shouldn't drive under the influence of love, but you feel so good you do anyway. In fact, you feel that you are driving on the freeway of love. It's love that keeps lifting you higher, not the bay bridge you happen to be crossing over, and when you come to a stop sign, you mentally add "In the Name of Love."
Then the radio really begins to play your songs. "Nothing Compares to U," it purrs, then "I Can't Help Falling in Love With You." Paralyzed by the congruence between the radio station and your feelings, you fail to move from the stop sign. Finally, the lights on the cop car behind you start flashing red and blue.
"Ahh," you think. "You light up my life."
The cop, who happens to be a person from the sex to which you are attracted, puts you through a routine sobriety test. "Every little thing she does is magic," you marvel. You pass the test but get arrested anyway, because you murmur to your arresting officer "You're the one that I want."
Being jailed doesn't bother you. You spend all night scratching the lyrics of Savage Garden's "Magical Kisses," the mushiest love song ever written, on your cell wall, which nearly causes you to be beaten up by your fellow inmates. You don't care. "I'll be there,' you whisper, imagining the scratchy jail blanket is your beloved, "just as soon as I make bail."
If this happens to you, you're in love. Oh yes you are. It's more than a feeling.
But what if your love is less than complete bliss? What if it is unrequited, meaning the one you love desires you less than a bill for back taxes? Or you discover that she not only loves you, but everyone else in your zip code?
The popular song rule will not fail you. Say to yourself, you can't hurry love. Resolve, I'm going to keep on trying, even if I hate myself for loving you, whether you're an Earth Angel or a Devil with a Blue Dress On, or even the girl all the bad boys want. Have a room reserved at the Heartbreak Hotel, and be prepared to shed tears on your pillow, if she decides that her boots are made for walking.
Stick to this formula, and you'll be able to decide whether love has passed your way or not. Eventually you may conclude that love's the finest thing around or, alternatively, that love stinks.
What makes you an expert on love? you may ask, in the surly fashion in which my readers sometimes treat me. Have you ever been in love? The answer is of course, yes. I currently am in love and while my beloved and I have passed through that first, blindingly pleasurable stage of mutual ecstasy we still care about each other deeply. We know each other in ways that are almost unfathomably intimate. For example, just a few days ago she insisted that I go out and purchase a twenty-four roll pack of toilet paper immediately, even though I was busy and we already had at least four rolls in the house, because of her GODDAMN OCD IRRATIONAL FEAR OF RUNNING OUT OF TOILET PAPER. I could have argued. I could have ridiculed. I could have spun those four rolls of toilet paper into the tree in front of her house and screamed "NOW WE REALLY ARE OUT OF TOILET PAPER!"
But I didn't. I meekly went and got the tp, because I realized if I didn't I would not get sex all weekend. And because I did, we did have sex. And it was good, down on the floor, deeply satisfying sex, right next to that huge unopened back of toilet paper WHICH PROVES WE REALLY DIDN'T NEED IT RIGHT AWAY IN THE FIRST PLACE!
All of the toilet paper-induced rage had left me at that point, though. All I could do was look at her fondly and whisper softly, "You're still the one."