I am a Manager in Training-What's a better way of saying this?

Trainee Manager? or you could try Junior Manager, Deputy Manager, Assistant Manager..
Although you really should go with whatever it says on your job description.

Just don’t confuse Trainee Manager with Training Manager, the two are very different things. ;)

They most certainly are….....I’m kinda fishing for Training Manager as my next title, but doing the training for it in college now :)

It sounds fine. Just put the hyphens in: Manager-in-Training.

maybe just state that you’ve had management training. That implies what you want without giving a time frame. You will most likely be asked the specific during the interview but it is better explained face-to-face. I want my resume to get me an interview, once my foot is in the door all the little things are easily explained. And please don’t mistake what I saying as advocating for lying on your resume.

Management trainee.

that’s a great way to say it @breed

Manager-in-Training is easily the best.