The following is from GotQuestions.org:
A genuine faith is one that not only believes in God (the devils themselves do that -James 2:19), but leads to open confession of sin and obedience to Christ's commands. Remember, we are saved by grace through faith, not by our works (Ephesians 2:8-9), but our works should display the reality of our salvation (James 2:17-18). Genuine saving faith will always produce works; a faith that is perpetually without works is no faith at all and saves no one.
Read more: http://www.gotquestions.org/signs-saving-faith.html