I told my friend I would sign a lease with her but I’ve realized I can’t live with her. How can I let her know without hurting her feelings?
You need to be honest with your friend. Both of you are lucky that you realized your change of heart before you signed the lease. Tell her that you gave a great deal of thought to the idea of living together and believe it might compromise your friendship — which you want to keep intact. If you let her know some of the reasons why you feel this way, without blaming her, that would help her get over what she might initially perceive as a personal rejection.