I've noticed that sometimes words are repeated in the hebrew text.

Gen 3:16 אֶֽל־ H413 to הָ·אִשָּׁ֣ה H802 Unto the woman אָמַ֗ר H559 he said הַרְבָּ֤ה H7235 I will greatly אַרְבֶּה֙ H7235 multiply עִצְּבוֹנֵ֣·ךְ H6093 thy sorrow וְ·הֵֽרֹנֵ֔·ךְ H2032 and thy conception בְּ·עֶ֖צֶב H6089 in sorrow תֵּֽלְדִ֣י H3205 thou shalt bring forth בָנִ֑ים H1121 children וְ·אֶל־ H413 will be for אִישֵׁ·ךְ֙ H376 [shall be] to thy husband תְּשׁ֣וּקָתֵ֔·ךְ H8669 and thy desire וְ·ה֖וּא H1931 and he יִמְשָׁל־ H4910 and he shall rule בָּֽ·ךְ׃ H0 ס

Does this mean "Greatly greatly thy sorrow" or "Exceedingly increase more and more thy sorrow"?

Also, the verb "will" does not appear in the Hebrew. Why do the translators -- King James, HISB, and HCSB -- add "I will" when there is duplication of a word like this?