What is the meaning of [Hope deferred maketh the heart sick]

When we have to wait indefinitely for our hopes to be realized, we become sad
and disillusioned.

The full saying is to be found in Proverbs xiii, 12: ‘Hope deferred maketh the
heart sick: but when the desire cometh, it is a tree of life’. In his
translation of the Bible, James Moffatt made the meaning clear to this
generation of ours by rendering it thus: ‘Hope deferred is sickening: it is
new life to have desire fulfilled. ’