Synonyms of sincere in English:

sincere


See US English definition of sincere

See UK English definition of sincere

See Spanish definition of sincero

adjective

1‘my wife and I would like to express our sincere gratitude for what you did’

SYNONYMS
heartfelt, wholehearted, profound, deep, from the heart
genuine, real, unfeigned, unaffected, true, honest, bona fide, earnest, cordial, fervent, ardent, devout
rare full-hearted
ANTONYMS

perfunctory, token

2‘Jean is such a sincere person’

SYNONYMS
honest, genuine, truthful, unhypocritical, meaning what one says, straightforward, direct, frank, candid
artless, guileless, ingenuous
informal straight, upfront, on the level
North American informal on the up and up
Australian, New Zealand informal dinkum
ANTONYMS

insincere, hypocritical, disingenuous, two-faced