思う

In a sentence

• 私は昨日の映画は面白かったと思う。

  I think the movie we watched yesterday was interesting.

  Here, '思う' is used to express personal opinion about a past event.

• 彼が本当にそう言ったかどうかは分からないけど、そうだったと思う。

  I don't know for sure if he really said so, but I think he did.

  In this sentence, '思う' indicates a level of uncertainty or conjecture based on personal belief.

• 旅行に行く前に、何を持っていくかよく考えようと思う。

  Before going on a trip, I think I'll carefully consider what to bring.

  Here, '思う' conveys the speaker's intention or decision about a future action.