How to love her agin ?

hi al , i know this wil sound like a stupid question but its realy important to me ! there is this girl that i realy loved before , but now i realy hate her and see her as nothing but a lier and a stupid girl , i gave up everything for her before and lost some of my best friends just to difend her in situations , wel i hated her becuse she talks to many other boys but im the only one she loves and she says that she is just friends with them nothing else , it contains late night calls with them and laghing and stuff like that , realy i donno what was realy going on ?? she always tels me that she talks to other boys and not to worry cuz its just friendship she says , any way she tels me everything that goes on , but i didnt like it so i told her to cut everything with them and chanjed my self into a devil im always tough with her and thats the way she understod in the tough way and stoped talking to averyone but it was to late cuza i hated her and she is stil beging me 2 love her again , what i dont understand is why she onlyunderstod in the tough way and does she really love me or am i imagining that ? should i love her agin ? was she truthful ? what should i do ?