Complex sentence: Bullingdon will grant Barry an annuity of 500 guineas for life if he leaves England forever and ends his marriage to Lady Lyndon; otherwise, with his credit and bank accounts exhausted, his creditors and bill collectors will see to it that he is put in jail.
Split into simpler sentences: Bullingdon will grant Barry an annuity of 500 guineas for life on the condition that he leave England forever and end his marriage to Lady Lyndon. Otherwise, with his credit and bank accounts exhausted, Barry's creditors and bill collectors will see to it that he is put in jail.