せっかく〜のに／から (sekkaku ~noni / kara) — despite the effort / since we've come this far

Effort made, a rare chance had — either wasted, or worth making the most of.

Formula (सूत्र ढाँचा)

Verb せっかく + V普通形 + のに／から

N せっかく + の + N

「せっかく」carries the sense of "at some effort, with a rare chance", and two kinds of sentence follow.
「せっかく〜のに」= that effort was wasted, what a shame: 「せっかく作ったのに、食べてくれなかった」= I went to the trouble of making it, but they didn't eat it.
「せっかく〜から／だから」= since we have this chance, let's use it: 「せっかく日本に来たんだから、富士山を見よう」= we've come all the way to Japan, so let's see Mt Fuji.
Read the のに or から after it to catch the feeling.

With a noun, 「せっかくの N」: 「せっかくの休み」= a precious day off.

せっかく作ったのに、食べてくれなかった。

せっかくつくったのに、たべてくれなかった。

I went to the trouble of making it, but they didn't eat it.

How it is built (कसरी बन्यो) 作る → た-form 作った → のに → putting せっかく in front gives regret: 'the effort was wasted'.

せっかく日本に来たんだから、富士山を見に行こう。

せっかくにほんにきたんだから、ふじさんをみにいこう。

We've come all the way to Japan, so let's go see Mt. Fuji.

How it is built (कसरी बन्यो) 来た → んだから → せっかく in front → it means 'let's make the most of the chance'.

せっかくの休みなのに、雨だ。

せっかくのやすみなのに、あめだ。

A precious day off, and it's raining.

How it is built (कसरी बन्यो) 休み is a noun → せっかくの休み → なのに → a feeling of regret.

Question: 1/3

「せっかく来てくれた＿、留守だった。」— to express regret?

💡 Hint: The effort was wasted.