If you are searching this, the question is a common one, and the honest first thing to say is that it is answerable, though probably not in the way you are hoping. There is no single tell. What there is instead is a fairly well-studied set of behaviors, and a second question worth asking alongside the first one.
Look for Three Things, Not Fifteen:
Understood, validated, cared for. Relationship researchers use perceived partner responsiveness as the organizing idea for what makes a bond feel…