Praise be to Allaah.
What we advise you to do is to let her go. Breaking your promise to marry
her is justified according to sharee’ah. The Messenger (peace and
blessings of Allaah be upon him) encouraged us to choose a wife who is
religiously committed, so look for such a one, and forget about this one,
and Allaah will give you one that is better than her.
note that for a man and woman to form a relationship and agree to marry,
with the conversations and meetings that that involves, is something haraam.
This has been explained in the answers to many questions on this site, such
as questions no. 20949 and
If you have
done any such thing, then you must hasten to repent from this sin and
resolve not to do it again.
yourself as religiously-committed, so you must adhere to the rulings of
Islam and avoid that which Allaah and His Messenger have forbidden. May
Allaah help you to the best of words and deeds.