Is it possible to earn back trust once it has been broken?
I find it extremely hard to trust again once it has been broken, but I do try my hardest (depending on the situation) to give them the benfit of the doubt and move on.
Do you ever fully trust that person again?
No.
Can everything be good as new? Can you forgive and forget?
It can never be as good as new, but there can still be a relationship - even if it means your just tolerating them for the sake of peace.
Do you forgive but never forget?
Depending on the situation again, but yes, I can forgive....but I will NEVER forget.