Her insincereness during the negotiations made it hard to trust any of her promises.

Her apology sounded insincere, so I couldn't accept it.

He apologized insincerely, glancing at his phone the whole time.

Her constant insincerity made it difficult for anyone to trust her apologies.

The politician's insincerities were exposed by the leaked emails, shattering public trust.

His apology was the insincerest thing he had ever offered, given only to avoid confrontation.