That depends on the relevant law where the disappearance occurred.
In NSW that law is the Innkeepers Act, which limits liability to a maximum of $100 per person. In Victoria it’s the Australian Consumer Law and Fair Trading Act of 2012, which limits the liability of an accommodation provider to $300 per unit of accommodation.
There are exceptions to this limit, for example if the loss was caused by negligence on the part of the accommodation provider, or if the guest’s property had been deposited with the accommodation provider for safekeeping, in which case the liability increases dramatically.
In Europe liability is limited to 100 times the daily price of the hotel room for a theft committed inside the hotel.
That’s potentially huge, and you can expect a hotel would go all out to prove their innocence.
If compensation is inadequate you might turn to your travel insurance policy but you’ll probably need a police report, receipts to prove ownership and value and confirmation that the hotel was not at fault.