Ysolda

Ysolda is a female Nord found in Whiterun, commonly near Dragonsreach.

She gives the player a quest involving delivering her a Mammoth's tusk, which she needs in order to give to a Khajiit.

She is also one of the NPC's which you can marry using the Amulet of Mara.

Mammoth Tusk Locations

 * During the Companion's Quest that takes you into Halted Stream Camp, you can find multiple mammoth tusks.
 * Any Mammoth and Giant camps (Note: Mammoths are guarded by Giants, who do a very large amount of damage at low levels.)