Passage
And he saith unto him, Verily, verily, I say unto you, Ye shall see the heaven opened, and the angels of God ascending and descending upon the Son of man.
And he saith unto him, Verily, verily, I say unto you, Ye shall see the heaven opened, and the angels of God ascending and descending upon the Son of man.
John 1:49 Nathanael answered him, Rabbi, thou art the Son of God; thou art King of Israel.
John 1:50 Jesus answered and said unto him, Because I said unto thee, I saw thee underneath the fig tree, believest thou? thou shalt see greater things than these.
John 1:51 And he saith unto him, Verily, verily, I say unto you, Ye shall see the heaven opened, and the angels of God ascending and descending upon the Son of man.
The verse centers on "saith", "verily", "shall", "heaven", "opened", "angels", and "ascending". It is saying that the verse draws attention to "saith" and "verily", so its meaning should be read from those terms before moving to application.
The prior verse says "Jesus answered and said unto him Because...", giving immediate footing for "saith" and "verily". 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 "verily" with trust shaped by these words, not by a vague optimism outside the passage.