N2 — outside your level filter

ことだろう

ことだろうkoto darouN2literary

savor + how very X it must be! — the written exclamation

ajiwau koto darou

how very X it must be! — the written exclamation

meaning: how very X it must be! — the written exclamation

あの日ひ、母はははどれほど喜よろこんだことだろう。

ano hi, haha wa dorehodo yorokonda koto darou.

That day, how overjoyed my mother must have been. neutral

初はじめて見みる朝日あさひは、なんと美うつくしいことだろう。

hajimete miru asahi wa, nanto utsukushii koto darou.

The sunrise, seen for the first time — how very beautiful it is. neutral

All examples3

how very X it must be! — an exclamation, more common in writing

あの日ひ、母はははどれほど喜よろこんだことだろう。
ano hi, haha wa dorehodo yorokonda koto darou.
That day, how overjoyed my mother must have been. neutral
初はじめて見みる朝日あさひは、なんと美うつくしいことだろう。
hajimete miru asahi wa, nanto utsukushii koto darou.
The sunrise, seen for the first time — how very beautiful it is. neutral
彼女かのじょはどれほど立派りっぱな指導者しどうしゃであることだろう。
kanojo wa dorehodo rippa na shidousha de aru koto darou.
What a truly admirable leader she must be. formal