And beware of those who do proclaim to know Him well, because they are either delusional or even deliberately lying.
OP, I wish to inform you that this is not consistent with scripture. Scripture plainly states that God is knowable, and records a long history of people misrepresenting Him (eg Jeremiah 29:31).
Experience has shown me that when a Christian speaks against the reality of knowing God, that one is making excuses for not having a close relationship with God (see 1 John 1:6), which means that they have departed from following their conscience and they carry guilt that is not atoned for. We who speak faithfully of our relationship with God have a natural effect of offending that one's jealousy, though we are innocent, because all that a human craves for is to be at peace with God.
In terms of who you should trust, certainly I do echo the effect of this poster, to beware (Jeremiah 9:3-6).
Even St. Paul describes that there is a gentleness in way The Holy Spirit speaks, that although we do plainly speak of hard truths, we do so such that is innocent in God's sight - and, as though we are speaking for God Himself:
But as we have been approved by God to be entrusted with the gospel, even so
we speak, not as pleasing men, but God who tests our hearts. For neither at any time did we use flattering words, as you know, nor a cloak for covetousness—God is witness. Nor did we seek glory from men, either from you or from others, when we might have made demands as apostles of Christ. But we were gentle among you, just as a nursing mother cherishes her own children.
1 Thessalonians 2:7-8
St. Jude writes too, that some are eager to gain followers by flattery:
These are grumblers, complainers, walking according to their own lusts; and they mouth great swelling words, flattering people to gain advantage.
Jude 1:16
.. yet, a Christian who speaks for The Holy Spirit will always lead the person to have a right relationship with Christ. If you ever do find yourself in a situation where two Christians are offering contending views, then do keep this in mind! .. Where is the one intending to lead you, and is that where you are wanting to go?