ありえないほど

noun

unbelievably; incredibly; to an unbelievable extent

Used adverbially to emphasize an extreme degree, often with adjectives or verbs. Literally 'to the extent that it's impossible to exist/be true'.

• 彼かれはありえないほど速はやく走はしる。

  He runs unbelievably fast.

• その映えい画がはありえないほど面おも白しろかった。

  That movie was incredibly interesting.