YOU SAID:

I need to go to the bank to certify to my documents

INTO JAPANESE

私の文書を証明する銀行に行きたいです。

BACK INTO ENGLISH

You want to go to the Bank to prove my documents.

INTO JAPANESE

私の文書を証明するために銀行に行きたいです。

BACK INTO ENGLISH

You want to go to the Bank to prove my documents.