I think most things can show true love. But Moon-Jupiter love is very different from Moon-Saturn or even Moon-Mars. It just depends on what works for you.

More than synastry, I find that I connect deeply to those who have similar natal charts aspects to me. Other people who also have Venus-Saturn or Venus-Pluto or Venus-Moon, etc instead of people who have aspects I don't like Venus/Uranus or Venus/Mars. Those people tend to have a compatible view on love and expression of that.

This is really hard to define! It's complicated because "love" means different things to different people!

For some, a partner who gives a lot of space and freedom is truly loving them.
But then we hear of a couple, married 68 years. They've worn matching outfits, EVERY DAY for nearly seven decades!

The aspects between charts of these two scenarios would be very different. I don't think there is a single answer!