Kierkegaard - Works of Love Part 2 Chapter 2

Love Believes all Things - and it is never Deceived.

Experience teaches that one acts prudently by NOT believing everything. Existence will test you and judges you every moment.

If someone says that one the basis of the possibility of being deceived one should believe nothing, then we can argue the opposite. You can expect good from even the lowliest fellow, for it is possible that his baseness is merely an illusion.  If we COULD judge every human, then everything would turn outward (external, superficial, acts ) and the God-relationship would be eliminated. Living would become easy; but empty.

Knowledge is placing these contrasting possibilities in equilibrium.  Mistrust is not equilibrium.  It tends towards evil, envy, spite, corruption.  Love understands that truth and deception both extend just as far and that in judging between possibilities the judger is revealed.

Giving one's money (or love) away willingly is not the same as being deceived  out of one's money (or love).  There is no desire to try to get it back.

In the light of the eternal, there is only one possible deception which is self-deception or giving up love.