Cool idea! I think your best bet to monetize is to pair this with another product/service. So, you give the company a solid consumer review for free. Then you follow that up by offering a full internal review for their use. You interview employees, look over processes, recommend changes, very valuable Intel.

Or you keep it online. You lead with, "consumer trust is vital to the success of any business, but it only works if potential customers can find you online". Then you pair the review service with and SEO or lead generation service.

If you don't do those things yourself, simply partner with someone who does and work out a referral kickback per client.

The third option, if you're playing the long game, is to turn business reviews into a brand. Once you have an established brand that people trust, you can leverage that brand with ads and upsells, premium features, etc.