To be truly KIND is selfless and filled with compassion and mercy which the carnal man can "mimic" but cannot deliver faithfully every day over decades of time.
That's how you know ... just watch over time.
Anyone can fake a "honeymoon" period and be on their best behavior for a time ... but the true ruach always manifests.
Those who walk by the Ruach of Yahuah manifest LOVE first ... true love speaks LIFE over all. This is not here and there but always and consistently over vast periods of time for the rest of that person's life.
Matthew 5:44 "But I say unto you, Love your enemies, baruch them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;"
The carnal man can barely tolerate people much less truly LOVE them ... this is reality. Without the RUACH of YAHUAH to TRANSFORM THAT PERSON into one of MERCY and COMPASSION ... all you'll end up with is religious behavior for appearance sake.
Authentic transformation by the Ruach of Yahuah manifests always in LOVE first ... authentic and truly humble ... repenting along the way as you see yourself with honesty and without filters ... and you cry before your Savior.
You cannot skip over this and just do "bible studies" and "word studies" ... without the RUACH it's all "tinkling cymbals and sounding brass" ... if HIS LOVE is not in it.
Walk in the RUACH and LET NO CORRUPT COMMUNICATION come forth from your mouth ... honor and love one another as Messiah loves us all ... forgive one another as Yahuah for Messiah's sake has forgiven you.
Let the Shalom of our KING Yahusha be upon each and every one of your households.