He makes you feel calm, not anxious

This is the one. Forget the butterflies — those are adrenaline, and adrenaline is not love. Real love, especially the early-stage version of it, feels like ground under your feet. You stop rehearsing what you're going to say next. You stop checking your phone after every conversation to decode the last message. The nervous system registers something it doesn't always find in another person: safety. Calm is the rarest thing early romance produces, and most people mistake its absence for passion. But the anxious loop — did he mean that, is he losing interest, why didn't he text back yet — is not romantic electricity. It is the body registering instability. The relationship that begins with calm has a much better chance of lasting than the one that begins with constant emotional turbulence. When you notice your own nervous system settling around someone, that quiet is the loudest signal of all.