未必 / 不见得: not necessarily
副词 / adverbs
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
S + 未必/不见得 + V/Adj
未必 (written/neutral) and 不见得 (spoken) express polite doubt: "not necessarily", "it's not certain that". They're softened negations: ideal for disagreeing without bluntness.
Compare:
• 不一定 = not necessarily (neutral, very common)
• 未必 = not necessarily (more formal, a bit more sceptical)
• 一定不 = definitely not (categorical!)
Examples
成绩好的学生未必适合做研究。
Chéngjì hǎo de xuésheng wèibì shìhé zuò yánjiū.Students with good grades aren't necessarily suited to research.
贵的东西不见得就好。
Guì de dōngxi bú jiànde jiù hǎo.Expensive things aren't necessarily good.
他说的未必是真话。
Tā shuō de wèibì shì zhēn huà.What he says isn't necessarily true.
Common mistakes
✗ 未必不 is a double negative → "quite possibly does": 他未必不知道 = he probably knows.
✗ 未必 isn't a prohibition.
✗ 不见得: ✓ *bú jiànde* (neutral 得).