Men: Making yourself vulnerable to a woman?

What does it mean when a guy makes himself vulnerable to a girl? Is there something to that? I like this guy (don't know if he likes me yet) and he recently made himself vulnerable to me after a small riff that we had. He basically opened up his emotions to me and told me about how he felt about the fighting between us. Perhaps he just trusts me enough and there's nothing more to it but I just wanted to know from a guy's perspective (women you can feel free to chime in too) if it means anything significant when a man opens up his emotions to a woman?