Sin = lovelessness
Love = Sinlessness

Those that abide in love, abide in God (1 John 4:16) and those that abide in God do not keep committing sin (1 John 3:6). We can abide in love by the Spirit perpetually (John 15) therefore we can live without sin perpetually. Love is simply treating others how you want to be treated as Jesus taught. Those that teach sin is inevitable post conversion teach the impossibility of abiding in Christ and love. This is to implicitly deny the incarnation of Christ, who came as we are, yet abided in love by the Spirit and never sinned.