Subject + 未必 + Verb/Adjective
未必 (wèibì) means "not necessarily" or "may not." It is used to express doubt or reservation about a claim, suggesting that something is not as certain as it appears. It is more literary than 不一定 and frequently appears in written or formal Chinese.
贵的东西未必就是好的。
guì de dōngxī wèibì jiù shì hǎo de.
Expensive things are not necessarily good.
他虽然读了很多书,但未必真正理解了。
tā suīrán dú le hěnduō shū, dàn wèibì zhēnzhèng lǐjiě le.
Although he has read many books, he may not have truly understood them.
这个方法未必适合所有人,你还是先试试吧。
zhège fāngfǎ wèibì shìhé suǒyǒu rén, nǐ háishì xiān shìshì ba.
This method may not suit everyone—you should try it first.