Passage
And He said to him, “Truly, truly, I say to you, you will see the heavens opened and the angels of God ascending and descending on the Son of Man.”
And He said to him, “Truly, truly, I say to you, you will see the heavens opened and the angels of God ascending and descending on the Son of Man.”
John 1:49 Nathanael answered Him, “Rabbi, You are the Son of God; You are the King of Israel.”
John 1:50 Jesus answered and said to him, “Because I said to you that I saw you under the fig tree, do you believe? You will see greater things than these.”
John 1:51 And He said to him, “Truly, truly, I say to you, you will see the heavens opened and the angels of God ascending and descending on the Son of Man.”
The verse centers on "said", "truly", "heavens", "opened", "angels", "ascending", and "descending". It is saying that the verse draws attention to "said" and "truly", 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 "said" and "truly". 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 "said" and "truly" with trust shaped by these words, not by a vague optimism outside the passage.