Hi I am level 32
Havent used any platinum yet
I saw you could train with platinum but the gains seemed to be crap so I just saved it
Can i trade platinum on jsp?
Can I trade it in game?
What is the best investment to make?

Ive been using bows leveling up becasue they were always the best of what I found
For level 33 though I got a boss sword that I am going to switch to.

yes
yes
purchase boosts with it, many people first do training cost reduction in the crystal shop as it reduces the cost of training in the training center.
many people say staff is best, because of healing. I'm not sure what to think of all of it but just lyk.