Complex sentence: Simba helps Kiara back up the cliff, before they, along with Nala, allow the Outsiders and Kovu to rejoin the Pride Lands at Pride Rock and even accept Kovu as his son-in-law and the future king and Kiara the future queen.
Split into simpler sentences: Simba helps Kiara back up the cliff, and they, along with Nala, allow the Outsiders and Kovu to rejoin the Pridelands at Pride Rock. Samba accepts Kovu as his son-in-law and the future king and Kiara the future queen.