Disappointment is inevitable. But to become discouraged there's a choice I make. God would never discourage me. He would always point me to himself to trust him. Therefore my discouragement is from Satan. As you go through the emotions that we have hostility is not from God bitterness unforgiveness all of these are attacks from Satan.
However it is debased or misinterpreted love is a redemptive feature. To focus on one individual so that their desires become superior to yours is a very cleansing experience.