Hi @shijingg
In the field Edit Options you have a section - Value Settings:
There in the Validation part you can select rule or script, and provide the validation logic based on your requirement.
Before directly executing the workflow and checking for the errors that may encounter in the selected script or rule, try executing that rule in the debug page and check for all test case scenarios, if every thing seems to work as expected, then you can select that rule in this validation section and then try executing the workflow.
I hope this helps.