Why is "sesame" not pronounced as "se" and "same"?

The word "sesame" is pronounced as "se" "suh" "mee", with 3 syllables. Why is it not pronounced as "se" "same", with 2 syllables?


The pronunciation is derived from the French original term which entered Middle English at the beginning of the 15th century:

1425; Middle English sisamie, from Middle French sisame, learned borrowing from Latin sīsamum, variant of sēsama, from Ancient Greek σήσαμον (sḗsamon, “sesame seed”),

(Wiktionary)