It is a hard thing to really prove, definitively. In my own subjective experience it seems like men work to change themselves and make themselves what women want them to be. They speak seemingly more passionately about their partners, and seem far more devastated by break ups. The idea that women last far longer after their spouses die than men do.
Granted, this could be a matter of dependency - men need women more than women need men in a lot of respects? Is this a contributor to love, or a separate thing altogether...?
Romeo and Juliet is a story of men and women who falls in love even though the family hates each other. However, in this story, the men dies because of the women he thought was dead. Well, the women die after. So you know what, the men loved deeper than the women. Some say that the women also dies because of the guilt of the men's death. Well, Juliet could have gotten the idea of killing herself after watch Romeo.
There is no legitimate evidence or way of truly knowing this of this. If you look at statistics for time invested for the other person and statistics about fidelity you would probably draw the conclusion that women love deeper. My wife loves me just as much as I love her. Also, in my opinion, there is almost no love that has more depth than a mother's love for their child.
Most women do not only love sensually but also love emotionally. When a woman loves you she always puts you in prayers. I am saying this from a personal experience. So, I feel women love deeper than men. I rest my case. I'm just trying to make common sense. Thank you.