Sincere is a distinctive girls' name in United States, ranking #3079 in 2005 with 52 recorded births. This places Sincere in the top 16% of ranked US girls' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2009 with 91 births ranking #2189. In 2005, approximately 1 in every 35,533 girls born was named Sincere. STABLE Recent data shows the name is currently stable.