This is a Pokémon fancomic made circa 2005 by Soara, also known as Pokemoa, Pokesho, Moata, moa151, Moa Caret, and moa^.
They've been publishing awesome Pokémon fanworks at pokesho.com since 2005 and still do to this day!
As of writing they're most active at their twitter: https://twitter.com/moa151/

This particular comic hasn't been ported over to the new version of their website, so I thought it would be a good idea to share it here.
I took this copy from the Wayback Machine: https://web.archive.org/web/20060423090502/http://www.pokesho.com/dc_sana/sana.html

The resolution is quite poor by modern standards. It would have neatly fit fullscreen in a 800x600 monitor as was common in Japan at the time.
If you enjoy this comic and would like to read something similar, I highly recommend the "DC Fuyou" series already uploaded here. It's a comedy by the same artist with a different Gardevoir who gets into a lot of embarrassing situations and outfits.

https://e-hentai.org/g/30568/ea0a4fafbd/

It certainly brings me back.

Base +6, FlurrieFour +7, Mantleknight +6, Harvest13 +7