What Began As An Adjective And Noble Attribute Has Now Blossomed As A Popular Boy’s Name In The US. Sincere Comes From The Latin sincerus, Meaning “pure” And “clean,” And Describes Those Who Are Genuine In Their Thoughts And Actions. A Quality That Can Be Hard To Come By, Sincere May Inspire Baby To Always Be Their Authentic Self. Although The Word Has Been Around For Centuries, Sincere Is Stepping Up As A Modern Personal Name. With An Appellation As Honest As Sincere, Don’t Be Surprised If Baby Always Says It How It Is.