Is it an obligatory to accept the Pledge before the Jewish court to have a share in the Hereafter?
The answer of Rav Hollander:
According to Maimonides, The Ben Noah, who accepted upon him the Seven Commandments, – in accordance with the Jewish tradition, has a share in the Hereafter. The importance of the Pledge is that the public declaration leaves a much greater impression on the soul than just a decision.
The rabbis Brit Olam also believe that after an acceptation the Pledge, Ben Noah can take over (if he wants) some Jewish commandments. On the other hand, Jews are obliged to take more care of Bnei Noah, who made a declaration to the Jewish court.