Provably is a synonym of attestably.
As adverbs the difference between provably and attestably
is that provably is with proof; in a provable manner while attestably is in an attestable way.
provably
English
Alternative forms
* proveably
Adverb
(
en adverb)
With proof; in a provable manner.
Synonyms
* demonstrably
attestably
English
Synonyms
* demonstrably
* provably