Yes, God does know the heart:
Jeremiah 17:9 The heart is deceitful above all things, and desperately wicked: who can know it?
Proverbs 14:12 There is a way which seemeth right unto a man, but the end thereof are the ways of death.
You may call Jehovah's Witnesses a denomination, but, by wide margin, mainstream Christianity considers Jehovah's Witnesses a cult, among others, with proven false prophets. If they're a denomination, so is Jim Jones, as he was also a liar that sucked in the gullible. You could paint your face and put on a red nose, proclaim you're the latter day prophet Bozo, come to rewrite the Bible and call yourself a denomination, but be prepared most would beg the differ: you're just a cult, with extra-Biblical false doctrines and false prophets.
John 1
1 In the beginning was the Word, and the Word was with God, and the Word was God.
2 The same was in the beginning with God.
3 All things were made by him; and without him was not any thing made that was made.
...
14 And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth.
These verses, alone, are crystal clear. As a matter of fact, all Jehovah's Witnesses do is try to rewrite them, as well as others. There is much other scripture, unlike a Jehovah's Witness even the likes of unregenerate Jews recognized the Lord Jesus claimed deity, John 8:58-59. Ironic how those the Lord Jesus called out as children of the devil, nonetheless, understood His claim of deity.
There's nothing to debate. If you're a Jehovah's Witness, you're a deceiver. What you need to do is admit that you don't believe the word of God of the inspired Holy Bible, that you choose to follow a foul, false prophet like Charles Taze Russell, have replaced the word of the Creator with the word of a creature, Romans 1:25, and realize the Spirit-filled child of God is always going to agree to disagree with you. If you're a Jehovah's Witness or supportive, in accord with them, 2 John 1:10-11, no difference, you're just a liar, the very deity of the Lord Jesus a primal revelation of the Holy Spirit, in the true believer. There's no point to debate for a true child of God, as you're just a deceiver and will continue to deceive.
For instance, you could jump up and down all day long, proclaiming the earth is flat, that you won't have it any other way, and a conversation with you would be wholly useless. There are already deity threads out the wazoo, that horse beaten dead so much so that the horse has turned to glue, all arguments presented. What you're really up to is trying to spread your cult beliefs, like ringing doorbells to try and snag some other gullible. Another debate is, in fact, stupidity, though there are plenty of trolls here who love disputing you can stumble into the ditch with. Fair enough?
What you need to do is to cease with your so-called debating against settled scripture, cease trying to diminish and discredit Jesus Christ, very God come to man in the flesh: that is, you need to repent of denying your God, repent of your lies and get saved.