in the insert behavior, set the redirect to pass a URL variable:
page.php?insert=true
on the bindings panel, click the plus button and select URL Variable, name the URL variable "insert" this will create a binding for the URL variable passed by the insert record behavior
In the access rules manager, create a new rule as:
Allow IF
For the Value, click the lightning bolt icon and select the insert URL variable.
For the Criteria use "="
For the Value, enter "true"
Add your insert success message to the page, and add the Security Assist show region around it, for the rule, select the one you just created.