We can only be come confident that our interpretation of the Scriptures is correct if our interpretation is in harmony with the Scriptures. So if we find a verse or verses which don't seem to fit with our understanding then we should question if our interpretation was correct or not. If we can't understand it, then we just have to wait until God reveals the answer/explanation to us.
I can't claim to understand the whole of the Bible, but we all start off with some foundational understanding and as we continue to read and study the Scriptures then hopefully, and by the grace of God, we'll come to understand more of it. And by sharing and discussing our knowledge and understanding of the Scriptures we help each other to learn more, and to recognise errors that we used to believe but later realise was in error. So we have to use our reasoning powers to search for the truth. As Solomon said, (Proverbs 25:2), "It is the glory of God to conceal a thing, but the glory of kings is to search out a matter", and Revelation 5 says we will be kings :):
9) They sang a new song, saying, “You are worthy to take the book, and to open its seals: for you were killed, and bought us for God with your blood, out of every tribe, language, people, and nation,
10) and made us kings and priests to our God, and we will reign on the earth.”