And you misunderstand, completely, the point that others make.
Firs,t define what you mean by "love" (because the word means different things to different people, and generally covers a range of emotions and behaviors), and we can test for it. And we can prove it to the same extent as science proves anything...provisionally, based on likely possibilities and the available evidence, and relying on the shared subjective nature of experience to identify the common elements that reflect objective reality.
Science doesn't say "first-hand experience is worthless" or that the subjective is necessarily wrong. But that first-hand experiences, singly and unconfirmed, are wrong. The process of science is, basically, just the extension and codification of leaning over to you buddy and asking "Did you see that, too?"
First-hand experiences are what science is based on, as AkuManiMani pointed out...but not individual first-hand experiences. We have definitive evidence that people are often wrong. We also have evidence that when large groups of people report on the same event, and when the event can be repeated and reported on by other groups, and the answers match up between them, it's likely to be true. And that's the major difference.
Any study with N=1 is unreliable. Any research that can't be replicated is unreliable. Any observation that can't be made by others trying to reproduce the research is unreliable.
And that's why much of this is excluded. Not because it's wrong (although evidence certainly suggests that in the case of spirits, psychic powers, and similar), but because there's no way to determine if it's right. And at the basic level, when one drills down into it, anythign that cannot cause a detectible effect cannot, in any meaningful fashion, be said to exist.
