Promises Not Fulfilled?

Verses about the heart being sick when a desire is delayed. 

"Hope deferred makes the heart sick, But desire fulfilled is a tree of life." Proverbs 13:12
"When my spirit grows faint within me, it is You who knows my way." Psalm 142:3
"Answer me quickly, O Lord; my spirit fails." Psalm 143:7 G
 "Have faith in God," Jesus answered. Mark 11:22 

The value of a word. The value of a promise. Whether or not someone made one to you, it seems you have partial responsibility in the fulfillment of the promise.

In God's case, our part is to keep faith, actively. Not just sit and wait for "it" to happen, but to be positively proactive. I really think that the biggest part is to not give up. "And let us not be weary in well doing: for in due season we shall reap, if we faint not." Galatians 6:9 (KJV)
So keep working at it. Do your part. Do what you know to be right. Do not sway to the left or right, do not compromise, but keep faith. Do not look for a short cut. If you fall, get back on your feet and finish the race. If it's in your heart, believe even when it seems impossible, because He can make a way where there seems to be none. Just don't give up yet. Finish what you started. Cross the finish line.

When a friend, or anyone else made you a promise, what is there to do?
I can think of two cases:
First, you do trust your friend, in a way that allows you to be flexible with your time. What he or she said, will do. It might take more time that initially thought.
Secondly, you have a back-up plan, in case it doesn't follow through.
Let me add a third one. You've decided on the outcome in your heart already. You gave.

When God gives you a promise, what is there to do?
"I am with you always, even to the end of the age." Matthew 28:20
"But in all these things we overwhelmingly conquer through Him who loved us." Romans 8:37
"And Jesus said to him, "'If You can?' All things are possible to him who believes." Mark 9:23

In the end, you might still get what you hoped for or needed, just not the way you expected it to happen. God said He's with you every day. God said He'll never fail you. God said if you believe, everything is possible.

May God bless you with an uplifting and beautiful day.