In Persian,
Shahrazad is pronounced shaw-raah-zahd,
Shahrizad is shaw-ree-zahd, and
Shahrzad is shaar-zahd. The first two are both variants of the last one (and not any other way around), if I am not mistaken. All three have almost even emphasis on the syllables, with the last syllable in each having just a little more weight than the others. It's not heavy enough to warrant upper/lower cases, but there is a definite slight weight on the last syllable. It's very difficult to explain; you would have to hear it spoken in order to really understand.
In English, it's sheh-he-reh-ZAWD, but that's just our Anglicized pronunciation.