U know it..u just know it intrinsically

All his actions and behaviors fade and his weakness will be openly visible in front of that girl, be while will be tough on other places where she isn't there.... But keeps to smile when he sees her

U never know

Eye contact,always with the staring but not in a weird way,always wanting to be with u in every excuse,always there when ur alone,talks alot about hims self(i am not sure if this is applicable for all)always giving you signs.....bezu alu gn hulunm ande aydelum yerasachew megelecha alachew

Make an eye contact

He always see you/eye contact

we dont have to tell you u girls think u know all about men so u now by default

He jerks off with your pictures