The phrase "real difference between someone" means that there is a genuine distinction or variation in qualities, abilities, or characteristics that sets one person apart from others. Full definition
The only real difference between people who want to build muscle and people who want to lose weight is the weight, number of repetitions, rest between sets, and what they eat. (thescienceofgettingripped.com)
There is a very real difference between good and evil actions and this difference is not only in how these affect others. (religion-online.org)
The lack of real difference between the playable characters means that there is no reason to play again. (gamesrevisited.com)