Innocence with a wink — the halo signals 'I'm being so good right now' but is almost always used ironically, right after admitting to something a little naughty or self-serving. That tongue-in-cheek 'butter wouldn't melt' usage is now so dominant that the sincere, literal 'angelic' reading has become the rarer interpretation.
Keywords: angel, angelic, angels, blessed, face, fairy, fairytale, fantasy, halo, happy, innocent, peaceful, smile, smiling, spirit, tale