* 勤勉 (kinben): This is a very common and general word for diligent, meaning hardworking and conscientious. It's a safe bet in most situations.
* 努力家 (doryokuka): This translates to "hard worker" or "person who makes an effort." It emphasizes the effort put in, rather than just the result.
* 熱心 (nesshin): This means "earnest," "enthusiastic," or "zealous." It suggests diligence driven by passion or strong interest.
* まじめで (majime de): This means "serious" or "earnest," and implies diligence through a responsible and dedicated attitude. It's often used as a descriptor of a person's character.
The best choice depends on the context. For example:
* "He's a diligent student." 勤勉な学生です (kinben na gakusei desu) or 努力家の学生です (doryokuka no gakusei desu) would both work well.
* "She was diligent in her work." 彼女は仕事に熱心でした (kanojo wa shigoto ni nesshin deshita) might be a good choice, highlighting her enthusiasm.
* "He's a diligent and serious person." 彼はまじめで勤勉な人です (kare wa majime de kinben na hito desu) combines seriousness and diligence.
Therefore, consider the specific nuance you want to convey when choosing the best word. 勤勉 (kinben) is a good starting point for most situations.