Dispatched with one pack inoperative; an A319 makes an emergency descent over water and diverts due to a failure of the bleeds providing air for the remaining pack.

Narrative

Emergency descent due to a loss of cabin pressure. The aircraft was dispatched with the number 2 pack deferred out of service. While flying over water; we got an ECAM message (#1 ENG BLEED FAULT) followed by the loss of cabin pressure. The captain initiated an emergency descent. Due to unfavorable weather over the nearest airport; the captain and I agreed ZZZZ would be a better airport. I notified the controller; declared an emergency and requested vectors towards ZZZZ. We completed ECAM procedures and were not able to pressurize with the #2 bleed through the cross-bleed. I notified our lead flight attendant of our emergency; our intentions; time remaining and plan of action. The cabin altitude climbed to approximately 11;200ft. Once the cabin descended below 10;000ft I established communication with our passengers and told them the type of emergency and that we would be landing soon. The landing was uneventful. Once the aircraft cleared the runway; the captain stopped the aircraft and had the emergency equipment team perform a visual inspection of the aircraft as a precaution. I communicated to our passengers that this was done only as a precaution and that we would be continuing the taxi shortly. Our lead flight attendant did an outstanding job communicating and calming our passengers; especially our Spanish speaking folks. Because of this; it is my recommendation that all future flights have at least one flight attendant that is fluent in Spanish. I strongly recommend not dispatching an aircraft with a single pack to fly to this part of the world.