Hmm, I don't know enough to give you a confident answer yet. The provided knowledge sources do not contain specific information on how to determine if an email is already registered using the ORY SDK. However, ORY provides various APIs and methods for user management and verification flows. You might find more detailed information in the [ORY Documentation](https://www.ory.sh/docs/).

I'm sorry, but the provided knowledge sources do not contain specific information on how to check if an email is already registered using the ORY API. However, typically this would involve making a request to the user management endpoint of the API and checking if the email exists in the response. For more detailed information, you might want to refer to the [ORY API Documentation](https://www.ory.sh/docs/reference/api).