1. Sincerity is a polite way to express sincere gratitude to the other party for their kindness and help. Gift is a kind of respectful expression, which not only expresses gratitude for the kindness and help of the other party, but also expresses modesty and sincerity when accepting the favor.
2. Sincerity is used to thank others for their gifts, invitations and help. Express sincere thanks. Politeness is usually used to accept other people's gifts, gifts, invitations, etc. In business and social occasions, express a kind of respect and gratitude.