EmilyDixon

OK, well I presume, you're looking to use Mega Gardevoir, check the two sets on the bottom of this page here. Additionally you could consider thunderbolt or Calm Mind in some form or another. However I'd say don't go with four attacking moves.

http://www.smogon.com/dex/xy/pokemon/gardevoir

Additionally the biggest threat to Gardevoir is Steel types like Scizor, Next you'll probably want to have something that can deal with that. Look for a fire type that fits what you want to do in my opinion.

Heatran?