Passage
And now I have told you before it come to pass, that, when it is come to pass, ye may believe.
And now I have told you before it come to pass, that, when it is come to pass, ye may believe.
John 14:27 Peace I leave with you; my peace I give unto you: not as the world giveth, give I unto you. Let not your heart be troubled, neither let it be fearful.
John 14:28 Ye heard how I said to you, I go away, and I come unto you. If ye loved me, ye would have rejoiced, because I go unto the Father: for the Father is greater than I.
John 14:29 And now I have told you before it come to pass, that, when it is come to pass, ye may believe.
John 14:30 I will no more speak much with you, for the prince of the world cometh: and he hath nothing in me;
John 14:31 but that the world may know that I love the Father, and as the Father gave me commandment, even so I do. Arise, let us go hence.
The verse centers on "told", "before", "come", "pass", and "believe". It is saying that the verse draws attention to "told" and "before", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 28's "Ye heard how I said to you..." into verse 30's "I will no more speak much with...", so "told" and "before" belong inside that flow. 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 "told" and "before" with trust shaped by these words, not by a vague optimism outside the passage.