Passage
And he saith to him: Amen, amen, I say to you, you shall see the heaven opened and the angels of God ascending and descending upon the Son of man.
And he saith to him: Amen, amen, I say to you, you shall see the heaven opened and the angels of God ascending and descending upon the Son of man.
John 1:49 Nathanael answered him and said: Rabbi: Thou art the Son of God. Thou art the King of Israel.
John 1:50 Jesus answered and said to him: Because I said unto thee, I saw thee under the fig tree, thou believest: greater things than these shalt thou see.
John 1:51 And he saith to him: Amen, amen, I say to you, you shall see the heaven opened and the angels of God ascending and descending upon the Son of man.
The verse centers on "saith", "amen", "shall", "heaven", "opened", "angels", and "ascending". It is saying that the verse draws attention to "saith" and "amen", so its meaning should be read from those terms before moving to application.
The prior verse says "Jesus answered and said to him Because...", giving immediate footing for "saith" and "amen". In John context, the local focus is the identity of Jesus, new birth, eternal life, and belief and unbelief.
A plain takeaway is to answer the verse's own emphasis on "saith" and "amen" with trust shaped by these words, not by a vague optimism outside the passage.