Underneath all of those lies is one true thing, one true thing that can support the weight of all the lies in the world, and that’s the fact that I love you. And you know that when I say that, I am not lying.
What she means :
The reason HIMYM finale was a tragedy lies in the last seconds where Ted and Robin get back together. Not only did the writers destroy the most interesting and romantic couple this show has ever had, but they also gave the annoying stupid excessive male character his happy ending while ruining the independent woman and the sensitive womanizer. Worse, they admitted Robin should have been The Mother, which would have been catastrophic since she's never wanted kids. Also, Ted was ready to marry any girl. Robin never left Barney's mind. For Ted, there has been Stella, Victoria, Tracy, etc. For Barney, there was only Robin. She was The One™.