I’m needing to do the same thing and almost got stumped by one simple step*…
To further clarify how to do this…
I have MC questions to which I included (in the question wizard) Display Message for both correct/incorrect feedback, with desired text.
At the page-level, I am processing the question when the Submit button is selected.
At the test-level, I disabled the option on the Behavior tab to ‘show feedback…’
To get the Results page to show the feedback that I added for Display Message action in the question wizard, you must go into the Results Designer, click on the Correct/Incorrect Tabs and then *click into the last item in the list. There you will see the option for Display message feedback. Select it to add it to the list of items that will be included on your Results page.
This is also where you can change the font for each of the items listed. For each row, deselect the ‘Inherit’ check box, and you’ll be able to modify the formatting.
Works like a charm!