You can get petty theft dismissed if the charges are dropped or there's not enough evidence to convict you of the petty theft.
Petty theft can be dismissed if there's not enough evidence to charge and convict you of the theft.
Most petty theft charges are just a fine and an maybe a few months or so in jail.
Petty Theft is not as serious as other theft such as felony theft though.
You cannot normally be convicted of theft or a crime without evidence to prove you stole the item they are accusing you of.
However it's pretty easy to have evidence that you stole something if you shoplifted etc as most places have cameras and a camera is enough evidence to see you stole and then they can easily charge you and convict you of theft.
But just someone saying you stole the item is not enough for conviction.
You can still be charged with theft even when you return the item you stole.
Although you returned the item you stole which is good you still did steal the item you returned so you can still be prosecuted and charged with theft.
Returning the stolen item or merchandise or whatever you stole does not get you off on the theft charge unless the person or whoever you stole the stuff from decides to drop the charges.
Returning the item you stole does show good on your part though and can help you in court.
Returning the stolen item can help you negotiate a plea bargain with prosecutors.
But returning the item does not serve as a defense in court for stealing the item in the first place.
The bet thing to do however is not steal anything to begin with.