We are using Nintex Responsive Forms, in the above task form, we have mandatory the comments in case of Rejected is selected by the Approver. However, form is submitting without comments in case of Rejection is selected.
MANDATORY APPROVER COMMENTS
+3
+11I had the same problem ...
and to solve this, use the Validation Rules on the form.
For example:
Approver=="Rejected" && isNullOrEmpty(CommentField)
This is to give you an idea 
The "Approver" and "CommentField" need to be changed to your naming conventions.
+3JazakAllah for ur answer, since I have multiple forms I cannot go for that solution. This capability is builtin by Nintex as seen in the screen but not working.
+11Selam.
The function as seen in screen, indeed, does not work I had same experience. Although you set to "Required" the validation does not work ... and that is why I used a Validation Rule within the form.
You need to open the approval section in nintex and add the RULE.
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