Here is a fail safe means of knowing when someone is filled with the Holy Spirit when they are talking with you. Jesus never misunderstood anything said by those with whom He conversed. As well, when The Disciples were filled with The holy Spirit in Acts Ch. 2 and became The Apostles thereafter they never misunderstood anything said by anyone. An example of this Divinely empowered kind of understanding is shown in the resolution of the Doctrinal issues between Apostles Paul and James in Acts Ch. 21. The difficult issues were quickly outlined, and the solution agreed upon by all concerned. The other procedural and strategic discrepancies experienced by Apostles Paul, Timothy, Mark, Barnabus, and others were not because of any misunderstanding or misperception, but were because of differences of mind and priorities well understood by all. Godly men can disagree and still understand each other quite well. So, whenever a person to whom we are speaking in a shared language misunderstands anything we say, even after they have asked clarifying questions, it is because they are not filled with the Holy Spirit as were Jesus and The Apostles, none of whom ever misunderstood anything said to them. This is so simple to do. Just speak with a person long enough to verify their comprehension about what we say, answer their questions, and then we can easily know if they are filled with The Holy Spirit. This technique avoids the problem of large variations in interpreting Scripture, and the tricky idea of whether or not our spirit witnesses with their spirit. Praise God our Creator for the capacities we have to observe and communicate with our spiritual brothers and sisters, and to identify those who are not walking in The Spirit.