Passage
I have yet many things to say to you: but you cannot bear them now.
John 16:12 (DRB)
Nearby Context
John 16:10 And of justice: because I go to the Father: and you shall see me no longer.
John 16:11 And of judgment: because the prince of this world is already judged.
John 16:12 I have yet many things to say to you: but you cannot bear them now.
John 16:13 But when he, the Spirit of truth, is come, he will teach you all truth. For he shall not speak of himself: but what things soever he shall hear, he shall speak. And the things that are to come, he shall shew you.
John 16:14 He shall glorify me: because he shall receive of mine and shall shew it to you.
Study Lenses
The verse centers on "things" and "bear". It is saying that the verse draws attention to "things" and "bear", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 11's "And of judgment because the prince of..." into verse 13's "But when he the Spirit of truth...", so "things" and "bear" 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 "things" and "bear" with trust shaped by these words, not by a vague optimism outside the passage.