のなんのってYou would not believe how...
のなんのって is a very casual exclamation used to say that something was extraordinarily intense. Depending on the situation, it can express delight, annoyance, shock, or comic exaggeration.
An emotional reaction, not a neutral measurement
This ending presents the description as an excited reaction: roughly, “It was so ... you would not believe it!” The ending itself does not say whether the experience was good or bad; tone, context, and any following consequence make that clear.
Three basic forms
The expression can finish the reaction by itself, or a consequence can follow to demonstrate just how extreme the situation was.
山頂は寒かったのなんのって！
You would not believe how cold it was at the summit!
AnalyzeThis is a complete trailing reaction; no further explanation is required.
昨日のライブは盛り上がったのなんのって、終演後もしばらく興奮が冷めなかった。
Yesterday's concert was so exciting that the excitement still had not worn off for a while after it ended.
AnalyzeThe second clause gives a concrete result showing the intensity.
あの旅館は静かなのなんのって、夜は川の音しか聞こえなかった。
That inn was unbelievably quiet; at night, the only thing audible was the river.
AnalyzeWith a na-adjective, keep な before the full ending.
In animated conversation
旅行、どうだった？
How was the trip?
Analyze楽しかったのなんのって！景色も食事も最高だったよ。
It was absolutely amazing! The scenery and the food were both fantastic.
AnalyzeThe energetic delivery is central to the effect; a flat, detached tone would sound out of place.
More examples
引っ越しの日は忙しかったのなんのって、昼ご飯を食べる暇もなかった。
Moving day was so hectic that there was not even time for lunch.
Analyze子どもたちは喜んだのなんのって、何度も箱を開けては中を眺めていた。
The children were absolutely delighted; they kept opening the box and gazing inside.
Analyze彼女の話は面白かったのなんのって、みんな涙が出るほど笑った。
Her story was unbelievably funny; everyone laughed until they cried.
Analyze会場はにぎやかなのなんのって、私には隣の人の声も聞こえなかった。
The venue was so noisy and lively that I could not even hear the person next to me.
Analyze海がきれいなのなんのって、私たちは日が暮れるまで浜辺から動けなかった。
The sea was so breathtakingly beautiful that we could not tear ourselves away from the beach until sunset.
Analyzeこのスープ、熱いのなんのって！舌をやけどするかと思った。
This soup is unbelievably hot! I thought I was going to burn my tongue.
Analyze