I'd say something like this:

Totally understandable! Feel free to try a sample anyway. You might enjoy the taste or find something different you like about it. No pressure, just happy to let you give it a try

I've first hand seen how in-store sampling still matters because it gives customers a firsthand experience with a product that social media and digital ads can't fully replicate. I've seen people who mentioned they've seen the brand before but never tried it. With the sampling, people can taste, try, and evaluate a product for themselves, which helps build trust and confidence in their purchasing decision. Sampling also creates personal interactions where questions can be answered in real time, making the experience more engaging and memorable than simply seeing an ad online.

Someone is trustworthy when they are professional, reliable, and authentic in every interaction. When representing a brand in public, it's important to communicate product information accurately, be approachable and respectful, and follow all brand guidelines. Trust is built by being honest and also being confident in what you are sampling. I've organized several in-person demos for CPG and feminine health brands at grocery stores, including Whole Foods, so I am well-versed in representing a brand!