A Change Of Heart
How I Met Your Mother Season 6 Episode 18 (02/28/11)
The death of Marshall’s father motivates everyone but Barney to get his or her hearts checked out. Barney refuses to go to the doctor and adamantly denies he has feelings for Nora.
Before their second date, Barney comes down with a cold, but Nora nurses him back to health. Barney lies to Nora about wanting to get married and blackmails his friends into telling Nora that he is in fact a very sweet guy.
Robin contemplates getting a puppy but settles for a younger man to play with, but Marshall and Ted soon realize he acts more like man’s best friend than an actual grown up.
Barney realizes he actually has feelings for Nora but is too scared to act on them, which lands him in the hot seat with Lily who scolds him like a bad dog.