My advice would be to forgive her. She showed regret by sending you that email. She didn't have to. She sounds like she really wants you to forgive her and not be upset with her and that she feels sorry for what she did. Why live in discord if you can live with her in harmony and make her feel repentant and that she has turned over a new leaf for the good?
Maimonides teaches in Laws of Repentance 2:10 that it is forbidden to be cruel and difficult to appease, rather, a person must be quick to forgive and difficult to anger and when the sinner asks for forgiveness he should forgive him willingly and wholeheartedly."
The only question remaining is what to do about the stolen jewelry? Did she say she would return it or pay for its value? If so, you can certainly accept your property back and feel that what was not right has been fixed and made whole. But even if she has not offered to return the jewelry, it's your decision to forgo your rights to the property and forgive the monetary claim. It's your choice, and I don't know the circumstances of why she would not return your property if she is truly regretful, but perhaps she needed the money and sold the items. Perhaps speak to her in a gentle way and even give her a minor reprimand if you feel it will do you both good.
If, after speaking together you feel she is sincere and wants a positive and loving relationship with you, I suggest you seriously consider letting the past be the past and to look forward to a happy and successful future together. One of Judaism's greatest goals to seek is to pursue peace, harmony and unity. May God help guide you to say the correct words to her at the correct time and make you life as perfect and content as can be!
