Explanation
Expresses that something is not necessarily true; 'not always', 'not necessarily'.
Formation
Verb-casual + とは限らない, い-Adjective + とは限らない, な-Adjective + だとは限らない, Noun + だとは限らない
Detailed explanation
The ～とは限らない grammar point is used to express that something is not necessarily true or does not always occur. It can be translated as 'not always' or 'not necessarily' in English. The formation differs depending on whether it is used with a verb, い-adjective, な-adjective, or noun.
Examples
Itsumo benkyou shite iru to wa kagiranai.
It's not always true that I'm studying.
Takai shouhin ga ii to wa kagiranai.
Expensive products are not necessarily good.
Kare ga tadashii to wa kagiranai.
It's not necessarily true that he is right.
Ame ga furu to wa kagiranai.
It's not necessarily going to rain.
Practice
Grammar content sourced from hanabira.org.