If you are looking for a standalone file for a downloaded version, checking community forums like is your best bet, though native Portuguese subtitles for Brazilian shows are rarely uploaded there.
Do you need help for Episode 43 or a different language translation? Verdades Secretas: Primeiro capítulo (Bloco 1) - Globoplay Verdades Secretas subtitles Portuguese (BR) S01E43
Instead, you can access Portuguese captions and subtitles directly through official streaming platforms: If you are looking for a standalone file