One sided love pleaseee help me...am at the verge of ruining everything....?

hii...i know a girl since 12 years.....5 years back from now i shited to other city....n then i started missing her badly...i couldnot remove her thoughts....i fell in love with her...i started making myself enough good to comfort her in future ..i did a lot am at quite better improved position now...but when i proposed her she told she has a boyfriend....i was ok with that because it was her choice....but she started avoiding me badly very rudely now this thing started affecting me....n now i realize i am just feeling helpless.....i told her to say to me to forget her i ll do that but she did not say that till now just ignored what i messaged her.....i do not know what to do i want her in my lie n i want to forget her as well please please help me tell me what n how should i do,,next...