Guy's Behavior

What does this mean when he does this?

so i have this manager around the same age as me. We worked together and i knew him when he was just a regular employee like me. We've never talk much but until he became manager its like he's trying to tell me he likes me by his actions. I had this feeling he may like me because he is always helpful mostly to me and very nice but i dont want to make assumptions. Well i noticed a couple of times when im talking to a male colleague (work related stuff) he stands really close and either looking at his phone or some paper work. I was walking into work one day and sat next to a guy on a computer to check my email and clock in (he always sees this guy talking to me). He stands behind us at a desk fidgeting through his paperwork pretending like he's doing something. I can't tell if he's eavesdropping or what. Today, i was talking to this guy for a split second and he was across the room literally and then walked closer and was all behind me. My heart was pumping for a split second, I thought he was going to yell at me or something but i he walked away.. However, I noticed that whenever im talking to a girl, he won't care at all and just breezes by like nothing.

What does this mean when he does this?
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