I think it's SA-YO-NA-RA, if you mean "goodbye" in Japanese -- I thought this thread was about a new Bollywood actress.
I'm only posting this because you seem to be interested in the Eastern culture and I believe it would do more good than bad.
It's really simple.
The main kana sets are your simple vowels
A-I-U-E-O
followed by K
Ka-Ki-Ku-Ke-Ko
followed by S
Sa-Si(shi)-Su-Se-So
and so on. almost always, the kanas end with a vowel.
SAIANARA would have to be broken down to SA-I-A-NA-RA, which would not make sense to a Japanese speaking person when pronounced that way.
I'm being a hypocrite here though - the Japanese will change the pronunciation of foreign languages to better suit their tongue. They like to add vowels at the end of words --
as an example -
War of the Worlds
wo o-bu za waa-lu-do