Who was the most optimistic love interest on How I Met Your Mother?

The most optimistic love interest on How I Met Your Mother would be none other than the protagonist himself, Ted Mosby. Throughout the course of the show's 9 seasons, Ted was shown to be not only incredibly romantic but also very hopeful about finding true love. Despite going through a number of different relationships, including those with Robin Scherbatsky, Stella Zinman, and Zoey Pierson, he never gave up on the idea of finding his soulmate.

Of course, Ted's optimism wasn't always well-received by his friends. Barney Stinson, in particular, often teased him for being overly sappy and idealistic. Nevertheless, Ted persevered and eventually found the woman he had been searching for all along - Tracy McConnell.

Tragically, Ted's happiness was short-lived, as Tracy became ill and passed away shortly after they were married. However, in the series' final moments, it was revealed that Ted's never-ending search for love had led him to his true soulmate, Robin Scherbatsky, with whom he had a longstanding, but complicated history.