You evolve the Pokemon; Ralts.
you can find kirlia on route 204
yes.
You find Kirlia on Route 203 and 204 using a Poke Radar.
A male Kirlia
route 203-204 south with pokeradar
route 203-204 south with pokeradar
kirlia and snorunt
It evolves when you reach lvl 30, which is a Gardevoir. But if you have a male kirlia and you use a dawn stone, you get a Gallade.
You cannot find Gardevior in the wild on Pokemon Diamond you will need to evolve a Kirlia. To catch a Kirlia you will need the Poke Radar. Now use the Poke Radar on Routes 203 and 204 and a wild Kirlia should eventually appear.
Ralts to kirlia lvl 20 kirlia female to gardevoir lvl 30 kirlia male to gallade use a dawn stone xD happy to help I get this info from http://serebii.net
Use Pokeradar in the grass right above Jubilife City. Ralts and Kirlia are available through pokeradar so If you get a ralts you can always evolve it if you can't find Kirlia.
Its kirlia If you have a boy kirlia use a dawn stone to evolve into Gallade if you want a gardevoir train to at least 30