Engagement with your translation provider is the key to verifying whether the people doing your translations have these skills. But substantial engagement with a knowledgeable person at a bulk translation seller is virtually impossible.
Japanese-to-English translators with neither Japanese nor English as a native language can look forward in the near future to replacement by machine translation systems suffering from the same handicap.
Many aspects of what happens to your documents after you order translations of them remain purposefully hidden from your sight but can affect accuracy, accountability, and security.
One troublesome characteristic of the Japanese language is the uncertainty of how Japanese personal names are pronounced. Many names can be pronounced in numerous ways, the pronunciation options sometimes being totally different. The problems involved are more more troublesome than Green or Greene.