What this boy behaviour mean?

When a guy or a boy knows you like him and chasing him for a long time and after a while he start looks at your body (body, boobs, ass) and at your waist in front of you, and sometimes he acts care of you (he gets shy around, he looks at you and look and his friend helps him and they act silly to take attention) and sometimes he acts he doesn't care at all!
What this boy behaviour mean?
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