Explanation
Expresses 'not difficult to ~' in a formal/literary sense; e.g., 'not hard to imagine/understand'.
Formation
Verb-dictionary form + に難くない (commonly with 想像する, 理解する, 察する, etc.)
Detailed explanation
The ～に難くない (～にかたくない) grammar is typically used in formal or literary contexts to indicate that something is not difficult. Common expressions include 想像に難くない ('not hard to imagine'), 理解に難くない ('not difficult to understand'), 察するに難くない, and so on.
Examples
Kare no yorokobi wa souzou ni katakunai.
It's not hard to imagine his delight.
Kono kekka ga kanojo o shitsubou saseta koto wa rikai ni katakunai.
It's not difficult to understand that this outcome disappointed her.
Kare ga okoru kimochi wa sassuru ni katakunai.
It's not hard to guess why he is angry.
Kono youna joukyou ga okotta riyuu wa souzou ni katakunai.
It's not hard to imagine why this situation occurred.
Practice
Grammar content sourced from hanabira.org.