The scene was taken from the "Sister of the Bride" episode, in which Blanche is upset because her brother is going to marry his boyfriend.
"I can accept the fact that he's gay," she tells Sophia. "But why does he have to slip a ring on this guy's finger?"
After hearing this, Sophia and Blanche engage in a short conversation about why people decide to get married in the first place and Sophia ends the argument saying,
"Everyone wants someone to grow old with. And shouldn't everyone have that chance?"