en_tn/tit/01/04.md

a true son

Since Titus was not Paul's actual son, this could be translated as "you are like a son to me." (UDB)

our common faith

our common faith - This could be translated as "the faith in Christ that we both share" or "the same teachings that we both believe in."

Grace, mercy, and peace

This was a common greeting. This can also be translated as "May grace, mercy, and peace be yours" or "may you experience kindness, mercy, and peace within."

Christ Jesus our Savior

Christ Jesus our Savior - "Christ Jesus who is our Savior"

For this purpose

This can also be translated as "This is the reason"

I left you in Crete

This could be translated as "I told you to stay in Crete."

that you might set in order things not yet complete

that you might set in order things not yet complete - "so that you would finish arranging things that needed to done"

ordain elders

That is, "appoint elders" (See: UDB) or "designate elders"