Albert Barnes Commentary Ecclesiastes 7:28

"which my soul still seeketh, but I have not found: one man among a thousand have I found; but a woman among all those have I not found." — Ecclesiastes 7:28 (ASV)

One man - One whose good qualities quite satisfy our expectation. Compare the expression one among a thousand (marginal reference).

A woman - The number of Solomon’s wives and concubines (1 Kings 11:3) was a thousand.