Complex sentence: Jess-Belle, determined that Billy-Ben Turner and Ellwyn Glover not marry, enlists the aid of a local witch who casts a spell that makes Billy-Ben forget Ellwyn and fall madly in love with Jess-Belle.
Split into simpler sentences: Jess-Belle is determined that Billy-Ben Turner and Ellwyn Glover not marry. She enlists the aid of a local witch who casts a spell that makes Billy-Ben completely forget Ellwyn, and fall madly in love with Jess-Belle.