How I Met Your Mother has introduced us to the mother. This reveal took place to close out Season 8, as seen here.
Will we finally meet her? Watch this promo now for the How I Met Your Mother season finale.

How I Met Your Mother Season 8 Episode 24 Quotes

Robin: A week from today we are going to be legend, wait for it...
Barney: Married!

I would open a vein in my arm if I could bleed that locket out, just to make her happy.