וְאֶת־אֲחִיכֶ֤ם הַקָּטֹן֙ תָּבִ֣יאוּ אֵלַ֔י וְיֵאָמְנ֥וּ דִבְרֵיכֶ֖ם וְלֹ֣א תָמ֑וּתוּ וַיַּעֲשׂוּ־כֵֽן׃
너희 말째 아우를 내게로 데리고 오라 그리하면 너희 말이 진실함이 되고 너희가 죽지 아니하리라 그들이 그대로 하니라
Rashi
ויאמנו דבריכם— means so shall your words be verified and confirmed. Other examples are, (Numbers 5:22) “It is true, it is true (אמן אמן)”, and (1 Kings 8:26) “Let thy word, I pray thee, be verified (יאמן).”
Sforno
ולא תמותו, he meant that they would not die here, as he was able to have them killed also in the land of Canaan if they would not come back of their own free will.