Jonn promises Jiller that he will bring Rowan safely back to her from their quest. All through their journey, even at the very end, the most important thing for him is seeing Rowan safe, as he had promised Jiller he would.
Marlie, Allun and Jonn all comforting Rowan when they see he is afraid during their quest.
Allun's explanation of how he regained his senses after seeing an illusion of his mother in the swamp just in time to rescue Rowan and Marlie from being pulled underneath the mud and drowned:
Allun (to Marlie): I heard Rowan's voice calling your name. And it was as though I were waking up from a dream.
At the very end, Rowan is back in Rin and sees his mother running towards him with her arms open and love, joy and relief plain on her face. He finally ends up understanding his mother's love for him, and accepts his mother and Jonn's relationship.
This line at the very end:
Jonn: I promised that I would bring your son home to you. But it is Rowan who has brought me home. He made me go on when I would gladly have fallen and died. He fought cold and fire for me, when he could have saved himself. He faced the Dragon alone.
The people of Rin's obvious acceptance of Rowan after hearing of what he had done on the Mountain, to the point that they are cheering his name in joy.
Rowan and the Travellers
Allun and Sara are seen to care greatly about the Travellers, and it's also seen that the Travellers care greatly about them. It's not surprising, given that Sara spent a lot of time among them and Allun was born there.
Sara's necklace turns out to be a Traveller reed pipe given to her by Ogden when she left to return to Rin, to be played when she needed their help. They cared so much about her that they were willing to risk their lives (if it came to that) to come to her aid.
Ogden telling the tale of how Rowan, Allun and the Travellers saved Rin from the Unrin trees at the very end, while everyone (Rin and Travellers) sits around the fire and listens with awe. There is no animosity as there was in the beginning, and no suspicion. It's just a group of people sitting around a fire enjoying a good (and true) tale.
And there's this:
'Now!' he said, looking around and plumping his hands on his knees. 'Could anyone spare a poor, useless Slip some dinner?'
And there wasn't a person there who didn't run to do his bidding.
Ogden thanking Rowan for saving the life of his adopted daughter Zeel, and giving him a bag of jewels and a reed pipe as a gift. A reed pipe which allows him to call on the Travellers for help at any time, from anywhere.
Rowan and the Keeper of the Crystal Rowan and the Zebak
Rowan sets off to rescue his captive sister from the Zebak land because he loves her and blames himself deeply for her capture, and he intends to go alone because he can't bear the thought of his friends being put in danger in a quest he feels is his alone to complete.
Sad though it is, Bronden's reaction to Annad's kidnapping counts as this. Here we have an otherwise grumpy and stoic character who is usually a jerkass towards the heroes, and she's crying silently at the thought of what has happened to Annad.
Rowan of the Bukshah General
Marlie and Allun's relationship. At first it doesn't seem like they are even romantically involved, but there are hints left through the series which make their betrothal at the end of book four not so surprising. In Rowan of Rin, when Allun reveals that he cannot go on any longer up the Mountain because he cannot swim, Marlie breaks into tears and hugs him, promising to return soon. In Rowan and the Travelers, Allun is terrified when Marlie succumbs to the sleeping spell that is spreading through the village.