Sincerity is the virtue of one who communicates and acts in accordance with their feelings, beliefs, thoughts and desires.

Sincere may also refer to:

• Jean Sincere (1919–2013), American film, television, theater and voice actress
• Lamont Sincere, American singer, songwriter and record producer
• Salvatore Sincere, American professional wrestler
• Seth Sincere, Nigerian footballer

• Sincere (MJ Cole album), a 2000 album by MJ Cole
  • "Sincere" (song), its title track, released in 1998
• Sincere (Khalid album), a 2024 album by Khalid
• "Are You Sincere", a 1957 song by Andy Williams, later recorded by Elvis Presley

• Sincere Department Store, a Hong Kong department store
• Sincere voting, casting a vote for an outcome that the voter prefers above all others