Translation:His mask is too scary for little children.
I translated "Son masque est trop effrayant pour les petits enfants" as "Her mask is too frightening for the little children" and got it wrong! I think you need to rework the criteria here.
When you're at least 90% confident that your answer is valid, you can just report it instead of commenting here.
Is there supposed to be a liaison between trop and effrayant or is that just an artifact?