So I am going to get on a soap box here and it is not meant to offend, only to share my feelings on the importance of HUMAN RESOURCES as a strategic function of your organization.
A person not being up to speed is a problem faced by many bankers... but it is a problem of the bank, not the person. All too often we either find ways to make excuses for this person and keep them around or we terminate them. In either case we don't acknowledge the problem the bank has and simply blame the person.
In your case you acknowledged not one but 2 problems many banks (big and small) have.
First you hired someone with no experience... so let's assume the basis of hiring was they seemed capable enough to do the job. That in and of itself is the start of a recipe for disaster, but in and of itself is not a negative. So hiring without experience is relatively neutral to the final outcome...
However, this makes me ask... What are your hiring practices? What are the requirements of knowledge, skills, and education needed to be a teller? What is in your job description for the position of teller? Do you have a job description for the position of teller (a lot of places don't)? Who does your hiring? HR staff? Branch Managers? Senior Managers? What is your interview process like? What questions are you asking which would indicate the person has the skills to do the job? What is your pay? Is it commensurate with what a person would expect for the type of work versus the job expecations? Is it high? Is it low? Is how you pay and how you hire even considered in terms of the bank's overall business and strategic goals? How does the teller position fit into the business and strategic goals of the bank?
I can ask about a million more questions, but they all make my same point. Hiring at your bank whether its to replace the janitor or the president should be a serious process with serious implications to the bank's overall success. Additionally, the hiring process should reflect the bank's value and culture. If the hiring process is wrong you're merely guessing at the ability of a person to meet, exceed or in most cases fall short of the expecatations.
The next problem you identified is poorly organized training. Your OJT may be fantastic, so I can't say the training is poor, but it is likely poorly organized. In the situtation above the poorly organized training can compound a hiring mistake... or simply make a good hire go bad. The person may be fully capable but without proper training can't perform the job duties. I like to say I have the cognitive ability to perform surgery, but without training i'd probably kill every patient.
Additionally the person may just simply not be able to handle OJT, but if you had a new teller workbook or something they might be able to grasp it no problem... or maybe not. So how are you measuring "ability" to perform the job without training? How are you gauging the effectiveness of the training for the employee? At my org we had compliance issues with lending rules... I asked a question, who thinks the way we currently do training is ineffective: I got 100% response stating it was ineffective. Well then thats MY problem as a compliance officer to fix, not the employees to know better.
Additionally there are probably parts of the job that are unique to your institution... so for example the order in which transactions is likely different than how my bank processes, so even someone with experience could get lost if not trained properly. I imagine they could pick it up "quicker" but that's not a garauntee either... which goes back to your hiring process
So my thing is consider hiring and training to be cut from the same strategic cloth... If your organization has no hiring process training should have to be more involved than OJT. If you have a solid hiring process, training should be as involved as needed to teach "the bank's way" in either case you still need metrics to gauge whether the person is getting it and whether the training is effective at helping them get it.
I could also go on for hours with regards to the uber importance of continuing training behind the new hire process but that's much more based on corporate culture than the problems you identified here.
In any event, regardless of how I feel, there are some immediate on boardining issues which you may need to address up to and including exactly what OSUCPA said.
What is prompting the manager to suggest the person isn't getting it, would be my starting point though.
In life, there is a lot less that could get better and a lot more that could get worse.
MBA Fin/MBS HR
My views only!