Complex sentence: Brynhild and Gudrun are arguing about whose husband is better, and Gudrun shows her the ring which Brynhild had given Sigurd, and recognizes and realizes she has been tricked.
Split into simpler sentences: Brynhild and Gudrun are arguing about whose husband is better, and Gudrun shows her the ring which Brynhild had given Sigurd. Brynhild recognizes the ring and realizes she has been tricked.