What is the most professional way to end an email to a potential client?

Ending an email to a potential client with "Sincerely yours," conveys a high level of professionalism and respect. This closing suggests a formal tone, which is appropriate when communicating with someone you may not know well or when establishing a business relationship. It indicates sincerity and a genuine approach, which can help in building trust and rapport.

While other options like "Regards," and "Best wishes," can also be acceptable, they may not always convey the same level of formality. "See you soon," is too casual for a professional context and implies a personal relationship or an expectation of a meeting that may not yet exist in a business setting. Using a closing like "Sincerely yours," sets the right tone for professionalism and establishes a standard that is often expected in business communications.