I’ll post anyway. I tried to get the italics to work, but no luck. I’ll use caps:
This from Etymology on Line: https://www.etymonline.com/word/good
Phrase FOR GOOD “finally, permanently” attested from 1711, a shortening of FOR GOOD AND ALL (16c.). Middle English had FOR GOOD NE YLLE (early 15c.) “for good nor ill,” thus “under any circumstance.”
One could easily see how a non-English speaking person could have a hard time understanding this usage.