Gemar chasimah tovah!
Literal Hebrew to English Translation: May you finally be sealed (in the Book of Life) for good.
Meaning: This greeting wishes others well in the new year.
Use: This greeting is used between Rosh Hashanah and Yom Kippur.
Right now, I'm struggling to forgive someone in particular for something he said, but it isn't easy. It would have helped if he had apologized when I told him that I had been offended.
UPDATE: I davened minchah in the shul where I knew he would be and wished him a gemar chasimah tovah, and he apologized. I think it's the hanhagah of Rava to do that, and it worked. I feel much better about forgiving him now.