Truth is, I’ll never know all there is to know about you just as you will never know all there is to know about me. Humans are by nature too complicated to be understood fully. So, we can choose either to approach our fellow human beings with suspicion or to approach them with an open mind, a dash of optimism and a great deal of candour.

The speaker foregrounds the limits of mutual knowledge: even in close relationships, people remain partly opaque to one another and to themselves. From that premise, the quote pivots to an ethical choice about how to live with uncertainty—either defaulting to suspicion (a defensive posture that treats the unknown as threat) or choosing openness, optimism, and candour (a posture that treats the unknown as an invitation to dialogue). The emphasis on candour suggests that trust is not naïve but practiced: we reduce misunderstanding not by demanding total comprehension but by communicating honestly and granting others interpretive generosity. The line functions as a compact argument for humane, pro-social skepticism—accepting complexity while refusing cynicism.