How do you write "the best is yet to come" in Latin and how do you pronounce it?

"Nondum non" means something like "not yet not". I hesitate to translate this since I'm sure it's for a tattoo, but it's probably something like "optima nondum venerunt" in a literal sense. There's a similar sentiment in Augustine, "Nam superiores dies anni huius iam transierunt, nec tenentur; futuri autem nondum venerunt." (For the better days of this year have already passed, nor are they being kept; the ones that are going to be have not yet come though.)