If you find the nearest Kwee Peddlefoot (located at your local faction head's hang out) and give him a /kiss, you'll receive Smitten, a one hour buff of +200 health.
|Cairne Bloodhoof (Thunder Bluff)|
|Lady Sylvanas Windrunner (Undercity)|
|Highlord Bolvar Fordragon (Stormwind)|
|King Magni Bronzebeard (Ironforge)|
|Tyrande Whisperwind (Darnassus)|
If you like the buff then consider participating in the Gift Collection part of the event (more on that later). The Kwee that gets the most gifts during "Love is in the Air" will stick around for an extra week after its over to continue giving the Smitten buff.