en_tn/deu/20/07.md

What man is there who is engaged to marry a woman ... Let him go home

"If any soldier here has promised to marry a woman, but has not yet married her, he should go back to his house"

so that he does not die in battle and another man marries her

The officer is describing a situation that could possibly happen to a soldier. If a man was engaged and died, another man could marry the woman, and the first man would not have any children. Alternate translation: "so that he will not die in battle, because if he dies, another man could marry her instead of him"