The compound word "心里话" is formed through a logical and metaphorical combination of its constituent characters: "心" (xīn) meaning "heart," "里" (lǐ) meaning "inside," and "话" (huà) meaning "words" or "speech." It literally translates to "words from inside the heart," constructing a noun that metaphorically signifies one's true, sincere, and innermost thoughts or feelings that are not typically uttered openly. The structure follows a common Chinese grammatical pattern of location ("心里" - in the heart) modifying a noun ("话" - words), effectively creating a single, cohesive concept for heartfelt sentiments or confidential truths.