Final answer:
The correct form of the verb to use in the sentence is 'performs,' which aligns with the singular subject created by the phrase 'Many an actor and musician.'
Step-by-step explanation:
The sentence in the question is related to a concept in grammar called subject-verb agreement. The phrase 'Many an actor and musician' forms a singular subject because of the use of 'Many a(n)', which is followed by singular nouns and requires a singular verb for agreement. Therefore, the correct verb form to complete the sentence is 'performs' giving us the corrected sentence: Many an actor and musician performs in front of live audiences despite suffering from stage fright.