真心 (zhēn xīn) is a noun meaning 'sincere feelings, genuine sincerity', often used with the measure word 片. It stresses feelings that come from the heart, while 诚意 (chéng yì) focuses on honest intention in one's actions or promises. 真情 (zhēn qíng) is more about true emotion or the actual situation, whereas 真心 emphasizes the authenticity of the feeling itself.