doubt someone's sincerity

Meaning

This expression means to suspect that someone is not being genuine, honest, or truthful in their feelings, promises, or apologies. It is used when you feel that someone's kind words or actions are fake or motivated by hidden, selfish intentions. The tone is skeptical, but the phrase itself is polite and formal enough for both personal and professional contexts.

Examples

• I don't want to doubt his sincerity, but he only offers to help when our boss is watching.

  I don't want to doubt his sincerity, but he only offers to help when our boss is watching.

• After she lied to me twice, I couldn't help but doubt her sincerity when she apologized.

  After she lied to me twice, I couldn't help but doubt her sincerity when she apologized.

• Many voters doubt the politician's sincerity when he promises to lower taxes.

  Many voters doubt the politician's sincerity when he promises to lower taxes.

• It's hard not to doubt someone's sincerity when their actions don't match their words.

  It's hard not to doubt someone's sincerity when their actions don't match their words.

• Although his apology sounded perfect, I still doubt his sincerity.

  Although his apology sounded perfect, I still doubt his sincerity.

Common Mistakes

• ✗ I doubt his sincere because he lied to me.

  ✓ I doubt his sincerity because he lied to me.

  Sincere is an adjective. After a possessive pronoun like 'his', 'her', or 'someone's', you must use the noun form 'sincerity'.

• ✗ I doubt about her sincerity.

  ✓ I doubt her sincerity.

  The verb 'doubt' is transitive and takes a direct object. You do not need to use the preposition 'about' after it.

• ✗ I suspect his sincerity because I think he is lying.

  ✓ I doubt his sincerity because I think he is lying.

  'Suspect' means you believe something is likely true (e.g., suspect his dishonesty), whereas 'doubt' means you lack confidence or trust in something.

Related Expressions

Practice

• It is hard not to ___ when they only reach out to you when they need a favor.

  💡 Use the full phrase meaning to question if someone is being genuine.

  Show answer

  doubt someone's sincerity

• When a salesperson is overly friendly, customers often ___ and walk away.

  💡 Adapt the phrase using the possessive pronoun 'their'.

  Show answer

  doubt their sincerity