I read it in the manga Berserk:
A child of only thirteen like master Adonis... How very cruel...
This is said when referring to Adonis's death, but is How very cruel grammatically correct? Or it is just a typo?
We use this term, although not very often and it's a bit old. The very is for emphasis. I looked in the ngram viewer for a more common term. The term "how interesting" occurs about 10 times as often as "how very interesting" in 1870, whereas in 2000, "how interesting" is about 50 times as prevalent.
If you want to play with the ngram viewer yourself (which looks in millions of books for specified phrases), you can find it here.