I disagree with the overall premise. Yes The word soulmate is a literary construct so it’s a bit exaggerated. However sometimes there is chemistry, there is a fit, (and sometimes not) and it’s not explainable. It’s nothing to do with having to work for it or some specific traits. I felt that way with my partner. We’ve been together for 23 years. Not that we don’t go through occasional problems but from the moment we met it was easy to be together. There was no hard work required ever. Easy, lightweight.