Complex sentence: Miss Snow's charms had ruined-or would have done so but for an accident-his moral character; as for Miss Maitland he had done his best to ruin hers, and had damaged himself grandly and irretreivably in consequence.
Split into simpler sentences: Miss Snow's charms had ruined-or would have done so but for an accident-his moral character. As for Miss Maitland he had done his best to ruin hers, and had damaged himself gravely and irretreivably in consequence.