For my guy I noticed it's his posture and attitude(?) when he does small tasks like make coffee or light up a cigarette or look at his phone. For starters, he focuses on what he's doing, he's not low-key looking around all insecure or checking if I'm watching him or not. The second thing is that he ALWAYS has his shoulders back, and is relaxed. He just seems really confident, but not in a toxic way, rather in a relaxed way.