The sentence
- In the play the incantations of the the witches completely accentuate/ accentuates the overall gloomy settings.
My question is should I use the "S" at the end of the word accentuate. Whilst I know as per the the sub + verb rules the correct form should be "accentuate" but I still have confusion regarding this as the sentence doesn't really sound correct to my ear when I elide the "s" at the end. Please guide.