IPA: /ˈpruːvənli/
KK: /ˈpruːvənli/
In a way that has been shown to be true or valid, without any doubt.
The method has been provenly effective in various studies.
Provenly → It is formed from 'proven' (from Latin 'probare', meaning to test or prove) and '-ly' (a suffix meaning in a manner). The word 'provenly' means in a manner that has been tested or proven.
Think of something that has been 'tested' ('probare') and is now shown to be true — that's why 'provenly' means in a proven manner.