Hi, Majid!
It's a difficult sentence, because while "friends" and "enemies" are opposites, "false" and "open" are not.
Tarheel is on the right track, but false friends ARE genuine enemies, so it doesn't quite get at your meaning.
So your original version might be best.
This doesn't answer your question, but we sometimes say "With friends like that, who needs enemies?"
That can refer to a false friend. It can also refer to a real friend who creates problems without meaning to.