What is a deceitful person? Why can’t deceitful people be saved?

What is a deceitful person? Why can’t deceitful people be saved?

Relevant Words of God:

If you are very cunning, then you will have a guarded heart and thoughts of suspicion regarding all matters and all men. For this reason, your faith in Me is built upon a foundation of suspicion. Such manner of faith is one I shall never acknowledge. Without true faith, then your love is far from true love. And if you even doubt God and speculate about Him at will, then you are certainly the most cunning of men.