This takes place after Sam calls Santana to find out what's up with Brittany during fondue for two, what we didn't see.
"Okay Britt, what's really going on, I know you better than anyone so you know you can't lie to me and I know something is happening. Talk to me, is it Sam? Cuz I will rip his guppy lips off and feed them to tubbs, if he's hurt you." Santana threatens
Brittany chuckles at that and Santana breathes a relieved sigh 'still got it' she thinks to herself.
"I got into MIT, early admission. I don't know what to do San, I'm so scared, what if I fail and I get laughed out, because I'm not as smart as they think I am?" There's tears coming out her eyes and Santana rushes to comfort her.
"Britt-Britt." She says in her most soothing tone. "You've always been a genius, you just have to believe in yourself. Someone really smart once taught me to accept myself through their love and now it's my turn to tell you. If you love you, as much as I love you, you won't pass this up and you'll kick some MIT ass. When you graduate I'll be there screaming the loudest and proudest as you walk across that stage."