Can guys really feel if a girl likes them?

I have this guy friend. I've liked him recently. I was told that how I interact with him changed, and that some of my friends felt that I already like him. My concern is, will this friend of mine know or feel that I started liking him? Will you guys know if your girl friend started liking you? How?
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+1 y
I was told that guys are observant. So I want to check if this is true
Can guys really feel if a girl likes them?
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