sincerity noun

ADJ. complete, deep, great, total | genuine, passionate | apparent ‘It's wonderful,’ he said with apparent sincerity.

VERB + SINCERITY doubt, mistake, question There seems no reason to doubt the sincerity of his beliefs. There was no mistaking his sincerity. | be convinced of She wasn't yet convinced of his sincerity. | demonstrate, prove, show

PREP. with ~