Intimate relationships are built on trust. If the trust is broken it can be one of the most difficult things to gain back. There is no time limit on when the person will trust you again. It is totally up to them. You have to admit you were wrong and not do whatever it was to cause the trust to be broken in your relationship in the first place. You have to be consistent, reliable and understanding if you truly love the person and they are who you want to be with. It may take a very long time. Unfortunately, you both may have to let go if they are unable to trust you again. My suggestion if you love someone cherish them and protect their heart. True love is so hard to find.