"Chúng tôi rất hiếm khi hạnh phúc."
Translation:We are very rarely happy.
Can this also mean "We are rarely very happy" or would that be said differently?
I THINK you'd need to put the rất after hiếm khi. Same word order as English.
in VNmese adverbs come before the word they modify. rất here is modifying hiếm khi not hạnh phúc. even if it is a bit off in English, there is nothing wrong in VNmese.