How do you know when you fall in love?

Actually,i cant give any correct answer to this qn.. Because I had never fallen in love with any girl... or atleast I think so.. I wonder if any one can answer this! I have also asked to many people the same question.. But all just slip away saying .."Cant tell How, U just know it".. may be that is the only answer 4 this..U just know it(or u just feel it).. I dont think Falling in love hurts But it's probably a kind of disturbing feeling. Well again, I must say I've sometimes felt heart disturbed, But it never lasted 4 long.. May be when this kind of feeling lasts 4 long they call it 'falling in love'.. Well have a great time... Also Plz inform me when u fall in love. ;) C ya...