Your tort can't digest sugars properly - they cause kidney and digestive problems - so tomato, fruit, carrot and bell pepper should only be fed very sparingly and very occasionally if at all.
Watercress is one of those foods that are O.K. to feed every now and again, but that few tortoises seem to want to actually eat.
Don't buy a lot until you see if your little friend will actually eat any.
Tomato is actually a fruit.