ないことには

expression

unless one does; without doing

Attaches to the stem of a verb to express a necessary condition: 'unless you do X, ...'. The following clause often states a negative outcome or impossibility. The note 'with verb stem' indicates it follows the -masu stem form.

• 実じっ際さいにやってみないことには、できるかどうかわからない。

  Unless you actually try it, you won't know whether you can do it.

• もっと勉べん強きょうしないことには、合ごう格かくは難むずかしいだろう。

  Without studying more, passing will be difficult.