What does Ruth 2:22 mean?

Naomi and Ruth are discussing how Boaz has blessed them by making sure Ruth can safely glean to provide for them.

Boaz told Ruth to stay near his "young women" (Ruth 2:8). When Ruth repeats Boaz's words to Naomi, she uses the more generic "servant" (Ruth 2:21) which the ESV translates as "young men." Naomi emphasizes to Ruth that she needs to stay close to the female servants. Boaz particularly told his male servants to neither reproach nor rebuke Ruth (Ruth 2:15–16). "Reproach" includes the concept of harm.

Naomi is more straightforward, not needing to use the polite, circumspect language of Boaz as a stranger and a man. Ruth needs to stay close to Boaz's female servants so the men cannot sexually assault her. If a man raped an engaged woman in a place where no one would hear her cries, like a field, the man would be sentenced to death. If a man raped a virgin, he was to arrange with her father to pay her dowry, marry her, and never divorce her—presumably if the woman and the father agreed (Deuteronomy 22:25–29). Although Ruth's standard of living would greatly improve if she were to marry, experiencing the trauma of rape isn't worth it. In addition, she is a foreign widow with no man to speak for her. The chance that she would be provided for and not discarded as damaged goods is slim.

As a single, un-engaged, foreign woman working in a field, Ruth likely knows this, but Naomi, as a loving mom, has the right to remind her.