If you actually listen to the song he is saying "No Woman, don't cry." Jamacian accents are hard to understand if you are not from Jamaica. The Japanese just need to chill out because this song means he doesn't want to see a woman cry because there is no reason for it. In his wife's book "No Woman, No Cry" she explains what he means in the prolouge:

"I had put his head in my arm, and I was singing "God Will Take Care of You." But then I started to cry and said, "Bob, please don't leave me." And he looked up and said, "Leave you, go where? [What are you crying for? Forget crying, Rita!] Just keep singing. Sing! Sing!"