A person can tell what kind of tree a tree Is by the fruit it bears -- apples, oranges, pears, etc. A tree standing by itself 'out of season' won't have any fruit on it's branches. And a tree can be identified by the kind of leaves it has.
A person can be 'known' whether he / she is a born again believer by observing their actions/ life. There are various qualities in a born again person's life (Christians' life) : love, joy, peace, longsuffering, gentleness, etc. etc. that will be observed. If those characteristics are Not evident in a person's life -- then other's can assume that they are Not born again. And they Can show concern for that person and take time to share in a loving, concerned manner how they Can become born again.
A person can be 'known' whether he / she is a born again believer by observing their actions/ life. There are various qualities in a born again person's life (Christians' life) : love, joy, peace, longsuffering, gentleness, etc. etc. that will be observed. If those characteristics are Not evident in a person's life -- then other's can assume that they are Not born again. And they Can show concern for that person and take time to share in a loving, concerned manner how they Can become born again.