豈図らんや

Adverb 豈 (ani, rhetorical interrogative) + 図ら (hakara, the irrealis of verb 図る (hakaru, “to think”)) + suppositional auxiliary ん (-n) (from -m, from -mu) + interrogative particle や (ya). Literally "(just) how could one think (such a thing so)?".

豈図らんや (hiragana あにはからんや, rōmaji ani hakaran ya)

1. an expression of surprise to an event that is contrary to one's expectations; unexpectedly, to [one's] surprise, contrary to [one's] expectations

• 意外 (いがい) (igai)
• 思 (おも)い掛 (が)けない (omoigakenai)