A really great question. In my experience, there is no single set of interview questions that get at that trait. However, you gain some sense of their capacity

A really great question. In my experience, there is no single set of interview questions that get at that trait. However, you gain some sense of their capacity for kindness in how they answer interpersonal questions, conflict resolution, and how they think about working with teams. Also, in my experience kind people tend to recognize other kind people. I often think this is what "culture fit" x-factors end up amounting to.