Sales pre-PMF should be done by the founders.
If you're the founder of an early stage startup and you're building a product that you're hoping other businesses will buy, you are capable of selling it. That's the good news. The bad news is that you're probably the only person capable of selling your product. That is, if you aren't able to sell your product yourself at first, chances are you're not going to be able to hire somebody else to do it for you.
Now, if you're anything like we were, you're probably thinking there are lots of talented salespeople out there. Wouldn't it be faster to hire one of them than try to do it ourselves? After all, that's what you probably do with any other role, like designers, lawyers, or accountants. The problem is that sales, before you find product-market fit, is very different from sales after you find product-market fit.
Sales pre-PMF is fundamentally entrepreneurial. It requires vision and credibility with customers, and lots of experimentation and a tight feedback loop with the people building the product. This is a role for founders.