godan verb (-mu), intransitive verb
be convinced; be under the impression; assume
Used when someone firmly believes something, often with と or と思い込む. It commonly implies the belief may be mistaken or too strong.
彼は自分が正しいと思い込んでいる。
He is convinced that he is right.
電車は
I was under the impression that the train left at ten.
godan verb (-mu), intransitive verb
make up one's mind; set one's heart on; be determined
Focuses on a firm personal resolve or fixed intention. Often appears in patterns like 一度思い込んだら, meaning that once someone has set their mind on something, they are hard to stop.
一度思い込んだら、彼は最後までやり通す。
Once he sets his mind on something, he sees it through to the end.
彼女は海外で働くと思い込んで、英語の勉強を始めた。
She set her heart on working overseas and started studying English.
godan verb (-mu), intransitive verb
be obsessed with an idea; fixate on; think about obsessively
Describes getting mentally stuck on one idea, worry, suspicion, or interpretation so strongly that it becomes hard to see anything else.
悪い方に思い込むと、どんどん不安になる。
If you fixate on the negative interpretation, you become more and more anxious.
彼は一つの考えに思い込むと、周りの声が聞こえなくなる。
When he gets obsessed with one idea, he stops hearing what people around him say.