Azula watched from her throne as Mai slid into a low crouch, only to come up in a deadly swing with several blades clutched between her fingers. She turned the upward momentum into a spin, bringing her right leg up into a roundhouse kick, before falling into a solid defensive position.
The princess would never call Mai beautiful, but temptation, perhaps. Her pale white skin offset by the dark hair common of the Fire Nation and her lithe figure betrayed the deadly woman that she really was. She was fluid grace as she moved through her practice routine. Mai had the patience and diligence to do anything she wanted, and it was one of the many things that drew Azula to her.
Mai must have felt the princess watching, because she suddenly made eye contact and executed a rather showy back flip. The torches that lit the room cast a glow behind her as she did it, and Azula could't help but think of the dragons that supposedly once roamed this land. Mai may not have been a bender, but she had all the grace that the firebender's ancient teachers supposedly had.
Yes, Mai isn't beautiful, but she is a temptation.