I know the answer to this question, because I did it the hard way. I was a qualified accountant with five years in audit, trying to persuade Goldman Sachs that I could be an effective salesperson. I faced continued scepticism. Auditors generally don’t make good salespeople, or so I was told. I managed to convince them otherwise, but it was a battle every step of the way.
What’s the easy way?
The truth is, it’s not really “easy” (although it definitely is easier than the traditional pathway).
Get any kind of sales experience, but make sure it is really, really difficult. Better to do an incredibly difficult sales job where you sell almost nothing, than an easy sales job where anyone sitting in the seat could have done the sales.
I wrote another article about the hardest sales job I had ever come across at https://www.linkedin.com/pulse/hardest-job-youll-ever-do-peter-harrison/. I found out about this company, because we interviewed multiple people at Goldman Sachs who had done this job, and we hired every single one of them. And they were awesome at sales
Let me know if you think there is a better way to convince your interviewer that you would actually be good at sales!