Leonard: Well, how about we stop being so scared of losing each other, and just be together?
Penny: That sounds nice.
Leonard: Good. I've loved you from the moment we met and I will keep loving you until the end of time.
Penny: Oh my God, that is the most beautiful thing anyone's ever said to me.
Leonard: Yeah? That's because you're beautiful, and your beauty fills my heart with love and song.
Penny: Getting kind of cheesy, Leonard.
Leonard: You think that's cheesy? Buckle up.
(Leonard gets down on one knee)
Leonard: Penny Hofstadter, will you please stay married to me?
Penny: Oh dammit, you topped it.