y did she lie to me :''''(

I have a friend I asked her sssomething coz I think sshe was single but she was not.
I ask her do u have a boyfriend she say no I don't have she swear to me that she don't have any boyfriend and I was liked ouh ok if like that. Then one day my friend say to me did u ever stalker her facebook profile and when I stalker her facebook profile I know that yes there is a guy in her life and its was shocking. Then one day suddenly while I was sitting besides her I asked her who is the guys she say he is a good friend of mine I still believe it. Then after that she give me her hndphone and say read the sms the sms describe that she going to break with her bf then I asked again do u have boyfriend and once again as usual she lie to me she ssay I don't have any bf. Then one day whole sitting wth my friend suddenly they tell me that she already have. Bf and my hear break in pieces its break into pieces I was really sad then after that after 5 days when I met my two friend again the girl has tell them something about me but they don't want to tell me maybe the girl said I only think imran as my friend not more than that and I know she say a lot of thing about me too I break I break I was about to cry but y did she LIE to me she can say straight forward isn't that she had a boyfriend but yes she made the hope and she break the hope after this I won't say anything to her she lie to me that make me so sad and yes just now I know he didn't break up with her bf she still with him I feel to cry when I'm writing this but no one knows who am I they no my name but not my heart :'''''''''''''''''''''(