Watermelon, rosewater-marinated feta and pistachio salad

I got this recipe from a New Zealand cookbook years ago before this fruit watermelon feta combo became a thing. It was great then, it is still great now. A perfect summer salad.

Verjuice is the sour acidic juice of unripe fruit. Named from the French vert (green) and jus (juice), verjuice, verjus, or vertjus, as it is also called, is literally 'green juice'. Its history stretches back to medieval, and perhaps even Roman, times when it was made with whatever fruit grew locally - crabapples, apples, gooseberries and plums. Contemporary verjuice is typically extracted from grapes.
Good verjuice is tangy yet mellow, with a light, fresh acidity underpinned by fruitiness. It is milder than vinegar, softer than lemon juice and more ascerbic than wine.