Have you asked your SM why you aren't a trainer yet? Also... I just want to make sure you know that being a trainer doesn't come with a raise in pay.

Being a trainer is a ripoff.

It sounds to me that the manager has a reason that they don’t want to make you a trainer, but doesn’t want to to tell you what that reason is. Ik this has happened at my store when someone asked to become a trainer. Rather than saying that the barista wasn’t qualified enough and hasn’t showed enough ability to be a trainer (which would have allowed them to improve in certain areas to become one), the SM just made up a thousand excuses.

Also, becoming a trainer isn’t that special. Ik it may seem like a step up from a barista, but it’s just another title that doesn’t come with a raise. To me it’s not really worth doing unless you want to become a shift.