I'm not sure she even gives you one in the first place but I'll look it up 4 you + I've
got all the gym badges and she has never given me one.

Apparently you only get it on Diamond after you get National Dex

need the national dex

You need the national pokedex to do it.You go to Bebe's house and she will give you an
eevee!

how do you get driflum in pokemon dimand besids going to the windworks

You have to beat the Elite Four and Dawn/Lucas will be outside of Rowan's office. She'll
tell you that "BEBE" is waiting for you. Fly to Hearthrome and go to Bebe's house, which
is next to the Pokemon center on the right. Talk to her and she'll give you Eevee. I think
you have to have an open slot in your party for Eevee though. Another way of getting Eevee
is going to the Poke Mansion, talking to the owner--he's in the right door when you
enter--and then go into the Trophy Garden--North of the entrance. You can find Eevee
there. Good luck!

you need to get national dex beat the elite 4 then talk to bebe