Classical Latin pronunciation would be:

Kī-sah-rā-uh

Hard "C" as in "cake," long "i" as in "fly," soft a, soft kinda-rolled r (if you know Spanish, it's not like "perro" but "pero"), long "a" as in "ate," soft unaccented final vowel

You may want to also try in /r/linguistics or /r/asklinguistics.

hi! before this thread gets sidetracked into a discussion of "Caesar", do check out this earlier post for reference

Original pronunciation of "Ceasar"?

edit: in particular, this thread