How to say "itself" in Japanese

• 自体じたいCommon
  noun (suffix), nounCovers emphatic 'itself': it singles out the thing itself as opposed to its surroundings, related matters, or details. Typical context: saying that the plan itself is sound even if the details are not.
  車くるま自体じたいは良よくも悪わるくもない。運転うんてんする人ひと次第しだいです。↗

  A car in itself is neither good nor bad; it depends on the driver.
• そのものCommon
  expression, noun, noun (suffix)Covers 'the very thing; itself', a stronger, more absolute emphasis: it presents something as exactly that thing and nothing else. Typical context: declaring that something is the very thing itself, not a mere imitation.
  彼かれは、彼かれらに親切しんせつそのものだった。↗

  He was kindness itself to them.

Both express emphatic 'itself': use 自体 to single out the thing itself as opposed to related circumstances, and 「そのもの」 when you want the stronger force of 'the very thing itself'.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 自体じたいitself
• そのものthe very thing
• それ自身それじしんitself
• こと自体ことじたい(the thing) itself