Explanation
Expresses the extent of something or emphasizes the degree of a condition or situation.
Formation
どんなに + Adjective + ことか, どんなに + Verb + ことか
Detailed explanation
The ～どんなに～ことか grammar point is used to emphasize the extent of a condition or circumstance, and to express how much or to what degree something is happening. It is often translated as 'how much', 'how greatly', or 'to what extent' in English. This pattern is usually used with an adjective or verb in a sentence.
Examples
Donna ni tsukareta koto ka, kotoba de wa arawasemasen.
I can't put into words how tired I am.
Donna ni tsurai koto ka, kanojo wa mainichi ganbatte hataraiteimasu.
How hard it must be, she works hard every day.
Kare no seikou wa donna ni yorokobashii koto ka.
How happy his success must be.
Donna ni tanoshii koto ka, minna de ryokou ni iku.
How fun it is to go on a trip with everyone.
Practice
Grammar content sourced from hanabira.org.