Please clear up this argument on Sin?

A friend of mine who claims to be a Christian, also desires sin and in effect accepts sin by hanging around those who are pagans, etc. yet justifies her ways by Paul's Romans verse in that we all desire sin. I tell her NO, although we are sinners, we should not accept this state and by sanctification we turn away from those sins, so we then cut out aspects of our lives that tempt us into sin. Her quick response is that I am being to "self-righteous" and judgmental. What would I say to her about sin that would be quick and simple?