The greatest indicator of future success in a coaching relationship is the rapport between a coach and client. Rapport is when the client trusts you and is comfortable openly exploring, including challenging topics or feelings, and you as the coach fully support the client throughout. Building rapport starts with a written agreement to begin earning trust. Rapport is developed further through the coach understanding and adjusting to the client.
Author Aniruddha Kumar defines rapport as “a term used to describe, in common terms, the relationship of two or more people who are in syncor on the same wavelengthbecause they feel similar and/or relate well to each other.” 
Techniques for developing rapport include matching and blending to the style of another. Most of us do this naturally with our friends and people we respect.
A coach, as a professional, is focused on their client. Coaches serve their clients by matching and blending with their client’s style. Specifically, to match and blend, the coach observes the client’s body language, rate of speech, and choice of words. The coach then matches some of their own to that of the client, blending their normal tendencies with the preferences of the client. As a result, the client feels the coach is in sync, and the client is more comfortable. Rapport is built and further developed.
