T-bill-ee-see
Here's a breakdown:
* T: Pronounced like the "T" in "tea"
* bill: Pronounced like the word "bill"
* ee: Pronounced like the "ee" in "see"
* see: Pronounced like the word "see"
It's important to note that the "i" in "Tbilisi" is pronounced like a long "e" sound, not a short "i" sound.