וַתֹּאמַ֖רְנָה־לָּ֑הּ כִּי־אִתָּ֥ךְ נָשׁ֖וּב לְעַמֵּֽךְ׃
나오미에게 이르되 아니니이다 우리는 어머니와 함께 어머니의 백성에게로 돌아가겠나이다
Rashi
For I am too old to have a husband. That I should marry him and bear sons, that you would marry them, for they would not be forbidden to you [to marry] and you would not be forbidden to them as far as [the prohibition against marrying] the wife of an older brother who died before he was born, for she [the widow] does require a levirate marriage because Machlon and Chilyon were not [halachically] married to them because they were gentiles and had not converted,15Had they converted before, their marriage would be binding and Rus would be prohibited from marrying Machlon’s yet unborn brother. The law of levirate marriage does not apply to a person born after his brother’s death. Marrying one’s brother’s wife constitutes incest when levirate marriage does not apply. However, since there was no binding marriage, Rus would be permitted to marry Machlon’s yet unborn brother. and now they were coming to convert as it is stated, “We will return with you to your people.”16Above, verse 10. From now on we will become one people.