The best way to take care of your concerns is to hire two candidates to help you run the café and see over a six to twelve month period who is better able to run the business. You obviously don’t need to have them there on the same days.
Many small businesses struggle with change management due to a lack of systems. While you were well it was fine you knew the operation inside out, but you will need to systematise certain operations like stock management and staff rosters that you can train your new assistant in. Alternatively, find someone who already has industry experience such as a bartender or chef that you can train up to run your business as a manager.
Honesty and integrity can be hard to come by, so offering an incentive over and above their wage or salary can be a good way to reward these characteristics. Be careful not to make an arrangement that gives away a percentage of your business though.
Know every number
Before you hire a replacement, make sure you know every number of your business. If you start noticing changes in the numbers you’ll be able to compare with what you know and figure out why the numbers have changed.