... Was she being sincere or sarcastic? I think it could go either way...
Simba did take a big slice out of a hyena to buy her time to escape, and when the three hyenas were about to make a meal out of them simba planted himself in front of her, protecting her in the process. By doing this he put her safety first.
But nalas personality is a bit sassy and sarcastic, and she could have been sarcastic at his pitiful roar and how mufasa had to save the two.
Your thoughts?