You have to use the detector app outside the hotel. It took me ages to find it and at first i thought it was going to be an unexplained mystery but you can find it.
In Pokemon Platinum you dont get the key from a grunt you get from the detective, before getting the key you have to go talk to prof. rowan in the library .
you can find the suite key by first going to valor lakefront [ not the actual lake the place with the resturant] use the pokemon watch app number 4 go to the regisration counter and walk out of it in the north direction, walk 1 step turn left and press A. the lady will give u a lava cookie if u go inside her house and talk to her.
There is no key, you must have a Pokemon with at least ten ribbons.
you will need the hidden items poketch app (sorry forgot the app name) go above the hotel grand lake use the poketch app a few times tell there is a dot than press A until it says your name found the suite key your name put the suite key in the key items pocket than talk to the lady she will go in the house go in the house for a reward she will give you a lava cookie which cures a Pokemon that has any status problem/condition
The key is laying on a table in the deepest part of the Pokemon mansion. You can find it lying on the table and it's used for opening the gym.
Truly I dont think you can get it in Diamond or Pearl version sorry.
you can't.
you have to go in front of the actual hotel building a couple steps in front of it with the item finder app and dont stand on top of it and press a.
its to the left of the exit of the hotel. use the item finder thingy around there and ull find it. it doesnt get you anything good so dont worry if you cant find it.
To find the suite key you use the dowsing machine app and use it near the registration booth outside and it will be a big dot.After you give to the girl she will give you a white flute and it lures Pokemon to you.Hope I helped you.
The Suite Key is northwest in front of the entrance to the beach of Route 213. You will need to use the Dowsing Machine Poketch App to find it.
first you need the dowsing machine and then outside by the reception you will find the suite key
Use your dowsing machine around Lake valor and you should find it neartwo homes
You have to find her suite key near lake valor she will unlock the suite if you give it to her go inside she'll give you the magna stone
You can only get it at a nintendo event but that already passed So your only hope is an action replay.
Find suite key and give it to the woman that is outside.
i dont think so