Use an imprest float
Keep the cash in a locked box or small safe, with the key held only by the custodian. Store the box away from the reception desk, where visitors and delivery drivers come and go.
An imprest system gives the custodian a fixed float, say AED 3,000. As money is spent, receipts replace cash in the box, so cash plus receipts always equals AED 3,000. When cash runs low, the custodian submits the receipts and is topped up by exactly the amount spent.
The beauty of the system is that any count shows instantly whether something is wrong. If cash plus receipts equals AED 2,860, AED 140 is unexplained.