Is it possible to change the message displayed for successful and unsuccessful applicants?

It is possible if you add an additional description in the setting of the option value.

There is an option value that allows you to add a message for the pass screen and a message for the fail screen.　　
When creating a question, please add the following option values.　　　　　　　　　　　　　　　[Title when passed]#messages_passed_title: (Text to be displayed)
[Text when passing] #messages_passed_body: (Text to be displayed)
[Title when failing] #messages_failed_title: (Text to be displayed)
[Text when failing] #messages_failed_body: (Text to be displayed)

example)
#messages_passed_title: Passed! congratulations! !
#messages_failed_title: Sorry... let's try again! !

Details are provided in the link below. Please refer to