Hi,
All fruit contains sugar. The better ones are berries, particularly raspberries and strawberries, but in rather small quantities and eaten with fat such as cream or full fat yogurt as part of a meal, not as a stand-alone snack. Some people can eat a small apple - a meter will tell you if you can. The definite sweet ones are mainly the tropical ones, and bananas should be avoided.
Hellmans Real Mayo has zero carbs so you can eat as much as you like. I do. If you buy another brand, have a look at the nutrition label for total carbs. Some are higher than others.