The Flintstones S01E09 - The Engagement Ring

Barney decides to surprise Betty with a belated engagement ring, which he gives to Fred for safekeeping, but Wilma discovers the ring and assumes it is a gift for her. Not wanting to shatter her dream, Fred decides to buy a second ring but doesn't have the cash, so he talks Barney into competing with a boxing champ in order to win a $500 prize. Wilma and Betty soon discover the plot and persuade the champion to let Barney win, not wanting any harm to come to the latter. Despite this, the champion still beats Barney, knocking him unconscious. Furious, Wilma and Betty assault the champion for double-crossing them and force the champion's manager to give the $500 prize to Barney. Afterwards, Barney manages to buy a new ring for Betty.