You may want to watch your copy of Assassin's Creed 3: Liberation carefully. A bug has hit the game that prevents loads from saving properly, keeping the player stuck in the loading screen. Ubisoft is investigating the problem.
CVG (via Pocket Gamer) reports that some users have reported a specific costume worn while saving the game before the bug struck. But some others don't share that common trait, so it's not necessarily the cause. Ubisoft is working on the problem, but has not said whether save data will be recoverable.
The company is encouraging players to contact Ubisoft Support directly. "They need to be made aware of what happens to recreate the bug and the amount of players it's affecting - that way they can push the issue up the chain."
In the meantime, you may not want to change costumes and then save the game, just in case that's the final diagnosis.