Senator Feinstein Seeks to Close Gitmo

Senator Diane Feinstein (D-CA) introduced a very important piece of legislation on Monday to close the Department of Defense detention facility at Guantanamo Bay within one year of the bill's enactment. The Senator noted that "Guantanamo Bay has become a lightning rod for international condemnation...This has greatly damaged the nation's credibility around the world. Rather than make the United States safer, the image projected by this facility puts us at greater risk. The time has come to close it down."

While I applaud Sen. Feinstein for this move, one piece of the bill gave me pause. She lists a range of different ways to process the detainees and includes this one:
"The detainees' home nations or a third-party government for further processing; there must be assurances that detainees will not be tortured or otherwise handled in a manner against international law."

While this sounds good in theory we have seen that diplomatic assurances do not work.
My question to the Senator is "How will you ensure that individuals sent home will not be tortured?"