Go away, all you who do evil,
    for the Lord has heard my weeping.
⁹ The Lord has heard my plea;
    the Lord will answer my prayer.
¹⁰ May all my enemies be disgraced and terrified.
    May they suddenly turn back in shame. Psalm 6:8-10

Here David knows his prayer will be answered. Do you think there was a waiting time between the knowing and the fulfillment? Is that how it works in your life?