Agree with the other posters, 50% of the value is a good offer. I sold mine years ago for a fraction of what we paid, not just appraised value, but actual payment. Engagement ring values decrease about 70% the minute they leave the shop or site.
ETA if you're not personally out the 45K I would take that half and run.
ETA if you're not personally out the 45K I would take that half and run.