Prince of Peace

Isaiah 9:6
For unto us a Child is born, unto us a Son is given; and the government will be upon His shoulder. And His name will be called Wonderful, Counselor, Mighty God, Everlasting Father, Prince of Peace.

What does it really mean to have God as the Prince of Peace? Does it mean we won't have turmoil, problems, sadness? Absolutely not. I think it means that through the turmoil, the pain, the sadness, we can rest on the assurance that God will bring us through it.

James 1:2-4

My brethren, count it all joy when you fall into various trials, knowing that the testing of your faith produces patience. But let patience have its perfect work, that you may be perfect and complete, lacking nothing.

Philippians 4:6-7

Be anxious for nothing, but in everything by prayer and supplication, with thanksgiving, let your requests be made known to God; and the peace of God, which surpasses all understanding, will guard your hearts and minds through Christ Jesus.

These verses do not imply that the peace of God keeps us from trials, but state that when in trials, we need to be encouraged because our trials will give us patience and continue to sanctify us. Instead of being discouraged by things, we should be joyous in the fact that God uses our frustrating circumstances to bring us close to Himself!
We aren't supposed to fret. We are to tell God about our problems and then leave them with Him. Don't continue to dwell on your problems; that won't give you peace! Instead, talk to the one person who will always care, God. And then let it be. Remember that sometimes, we need to be still and know that He is God. And we aren't letting Him be God when we continue to focus on our problems. His peace will guard your hearts, your minds, if you let Him.
To me, this is what the Prince of Peace is and means.