This quest is not available in game.
Bring 4 Gromsblood, 10 Giant Silver Veins and Nagmara's Filled Vial to Mistress Nagmara in Blackrock Depths.
Oh, the pains of love! My dear Private Rocknot is immune to my charms. I am spurned! It's maddening!
You must help me! We succubi know much of love, and I can make a potion to beat down the iron walls around Rocknot's heart. To make it, I need these items: the herb gromsblood, giant silver veins from the cliff giants of Azshara, and water from the Golakka Springs Crater in Un'Goro. You can place the water in this vial.
Please, <name>, help a poor soul in her quest for happiness!