Deep down beliefs: Edmund and Susan's sinerity

After reading in the Narnia books, two phrases caught my attention.
1.“Deep down inside him he really knew that the white witch was bad and cruel,” (LWW 97) thought Edmund as walked to her house about to betray his siblings.
2.Ï really believed it was him…I mean deep down inside,” (PC) said Susan (to Lucy) after she finally saw Alsan.

At first, each phrase seemed similar because each character is admitting that they believed something “deep down inside,” which they originally ignored, but after examining the phrases, it seems as though each phrase has a completely different meaning; one phrase is sincere and one is just a cover up.

In the Narnia books, we’re granted the privilege of “seeing” the character’s thoughts at times, which brings about one of the differences between these two phrases. Edmund’s phrase comes from his thoughts (what he was thinking and feeling at that moment), which leads me to believe that he was very sincere about believing deep down that the witch was bad. However, Susan’s phrase comes to us from the narrator telling us what she said. Since she was human, it is a possibility that Susan was thinking something else (about covering up her actions?) during the time of her “confession” to Lucy. Therefore, Susan’s statement makes me question how sincere she was in her belief.

Edmund’s actions of that same evening in which he said the phrase indicate that he knew deep down what was true but something else was driving him to the witch. First, we find out that Edmund had not enjoyed the Beavers’ supper because he was thinking of Turkish Delight (“bad magic food,” LWW 95) during the meal. Then after he left, and was trying to think about the queen, the narrator writes, “be he managed to believe, or to pretend to believe, that she wouldn’t do anything very bad to them…because all these people…are her enemies,”(LWW 96). Afterwards, the narrator adds, “At least, that was the excuse he made in his own mind for what he was doing. It was not a very good excuse, however, for deep down inside him he really knew that the White Witch was bad and cruel, (LWW 97).

Susan’s actions were very different. First, she snapped at Lucy for waking the group up to show them nothing but air and to accuse Lucy of dreaming. Susan forgets past events that Lucy usually turns out to be right in order to satisfy her own desire—to go back to sleep. Then, once she’s awake, Susan wines that Lucy has no right to boss them around because she’s the youngest and shows no desire to believe in anything Lucy says. Finally, as the group follows Lucy, one by one they begin to see Alsan, but the narrator points out specifically that during the walk, “Everyone but Susan and the Dwarf could see him now, (PC 160). It was not until the group reached the top of the hill at the stone table that Susan could see Alsan and said to Lucy, “I really believed it was him…he, I mean—yesterday…I mean deep down inside. Or I could have, if I’d let myself. But I just wanted to get out of the woods. (PC 161)

Especially because Susan added, “Or I could have, if I’d let myself,” makes her sincerity highly questionable. With Edmund, the narrator points out that he was trying to find excuses but with Susan, the narrator seems to be showing that Susan has plenty of excuses readily available and makes me doubt her sincerity.
What do you think about Edmund and Susan's sincerity?