The 33-year-old hinted he could quit after becoming a five-time Ashes winner last week.
He has since had "a really good talk" with coach Trevor Bayliss and captain Alastair Cook.
"I was as honest as I could be," Bell wrote in the Metro.  "Deep down I probably knew I wasn't ready to call time on my Test career."
Bell has played 115 Tests - only four Englishman have played more - scoring 7,569 runs at an average of 43 with 22 centuries.
He managed only 215 runs at an average of 26.87 in five Ashes Tests against Australia.