One's or ones possesive noun or not? [duplicate]
Solution 1:
One's
It's the one exception to the pronouns in not having a separate apostrophe-free genitive though historically there were others (it's and who's are now incorrect where one would use its or whose, but once upon a time this wasn't the case).
It can help one remember this, to consider that ones exists as the plural of other senses of one, and one's is a different word.