And true will be the weighing on that Day; and those whose weight [of good deeds] is heavy in the balance -it is they, they who shall attain to a happy state;

The balance that day will be true (to nicety): those whose scale (of good) will be heavy, will prosper:

The weighing on that day is the true (weighing). As for those whose scale is heavy, they are the successful.

And the judging on that day will be just; so as for those whose good deeds are heavy, they are the successful.

And the weighing [of deeds] that Day will be the truth. So those whose scales are heavy - it is they who will be the successful.