First, understand that your client's concern about "ownership" likely stems from their interest in control, flexibility, and long-term access to the website they're investing in. They might be worried about what happens to their website if they decide to stop using your services or if there are limitations on what they can do with their website.
Here’s how you can respond to client who might ask about this, although it isn't something that people will frequently ask:
"My company provides you with the technology and support to create and manage your website. While the platform is provided as a service, you retain full control over your website's content and domain. This means you can customize your site to reflect your business and take your domain and content with you if you decide to move to another service. This model allows us to offer you an affordable, low-maintenance solution for your online presence, with the flexibility to grow and adapt as your business does. Rest assured, this approach is pretty standard in the industry."