King James Version (KJV)
Set me as a seal upon thine heart, as a seal upon thine arm: for love is strong as death; jealousy is cruel as the grave: the coals thereof are coals of fire, which hath a most vehement flame. {cruel: or, hard}
Modern English
Set me as a seal on your heart, as a seal on your arm; for love is strong as death. Jealousy is as hard as Sheol. Its flashes are flashes of fire, a very flame of Yahweh.
Hebrew
שִׂימֵ֤נִי כַחוֹתָם֙ עַל־לִבֶּ֔ךָ כַּחוֹתָ֖ם עַל־זְרוֹעֶ֑ךָ כִּי־עַזָּ֤ה כַמָּ֙וֶת֙ אַהֲבָ֔ה קָשָׁ֥ה כִשְׁא֖וֹל קִנְאָ֑ה רְשָׁפֶ֕יהָ רִשְׁפֵּ֖י אֵ֥שׁ שַׁלְהֶֽבֶתְיָֽה׃
shiymeniy kaḥvotam ʿal-libeka kaḥvotam ʿal-zrvoʿeka kiy-ʿazah kamavet ʾahabah qashah kishʾvol qinʾah rshapeyha rishpey ʾesh shalhebetyah