Jonny Manz
I am who I am
It looks like Smolder’s thinking something along the lines of “Y’know, being stuck in Ponyville with only one other dragon, I’m glad it was you” - but she doesn’t realize she’s mumbling it to herself, and then Spike, who was distracted with something else, turns around and says “What?” - prompting Smolder to issue a denial of “Nothing!” just a bit too forcefully.