Sorry if this marks me as out of touch, but can you explain what you mean by a "love concert"? Does this have anything to do with Valentines Day on February 14th, and if so, what sort of event are you making out of it? How Christian / worship-y do the songs need to be?
How He Loves-David Crowder Band; Unstoppable Love-Kim Walker-Smith; Your Love is All Around-All Sons and Daughters; You Keep Loving Me-Jenny & Tyler; This is Just so beautiful-Jenny & Tyler; Relentless Pursuit-Kim Walker-Smith
All Christian bands/singers...
"Indescribable", Laura Story/Chris Tomlin
'Open up Your Heart and Let Me In.' God speaking to us in Come Away With Me: