How to say "Be" in Japanese

When translating "be" into Japanese, you must choose carefully between 売れる and 思い込む. In Japanese, 売れる (うれる (ureru)) is typically associated with "to be sold; to sell well; to be in demand" (Syllabus Level: N4) and represents Intransitive verb. On the other hand, 思い込む (おもいこむ (omoikomu)) maps to "to be under the impression that, to be convinced that, to be deluded into thinking" (Syllabus Level: N3) and represents To firmly believe something, often mistakenly, or to become deeply convinced of a belief. It implies a strong, sometimes incorrect, conviction.. A literal translation of "be" can often sound unnatural to native Japanese speakers if mixed up!