From: https://www.serebii.net/blackwhite/subwaymaster.png
Context: The character who says this to you (the player) is on the subway along with you. They are also about to battle you.
ようこそ おまちしておりました!
おまち means "long awaited" from what I can tell, but I'm having trouble understanding exactly what おまちする would mean. Does it mean "to wait a long time"?
What exactly would the full sentence mean then?