Here's how it breaks down:
* "for" - The "o" in this syllable has the schwa sound, represented by the upside-down "e" symbol (ə). It's a short, unstressed vowel sound, similar to the "a" in "about".
* "tune" - The "u" in this syllable has a longer, more distinct vowel sound.
So, the word "fortune" is pronounced with the schwa sound in the first syllable.