Complex sentence: Darcy's changed attitude and manners impress Elizabeth and lead her to consider reconciling their relationship; that deliberation is crushed when her younger sister Lydia elopes with Wickham in London.
Split into simpler sentences: Darcy's changed attitude and manners impress Elizabeth and lead her to consider reconciling their relationship. However, that deliberation is crushed when her younger sister Lydia elopes with Wickham in London.