I think it's how one might define love, if you're talking about grace and what is graceful in Twelfth Night. I think about Viola and how graceful she deals with the people she's in contact with in the play. To me she's fabulous, so I'm bias, but she's the greatest, along with a few of Shakespeare's other heroines, heroine defined in my desk dictionary as "A woman renowned for her courage and daring." That fits Viola, for sure.
She deals with Orsino as his employee loyally, diplomatically and gracefully, all the while wanting him to focus on her while he can't think of her as a woman, disguised as she is, enthralled as he is with Olivia.
She deals with Olivia gracefully, as Olivia falls for her, thinking she a he, disguised as she is as Cesario. She keeps Olivia at arms-length, never breaking her heart, true as she is to Orsino, all the while wanting Orsino to pay attention to her. How more graceful could she get?
And then she is so graceful with Antonio, she having had to defend herself in the comical encounter with Sir Toby, Antonio, happening by, thinking she Sebastian, his friend and her brother; Antonio getting arrested for an earlier crime, and she, sweetheart that she is, offering at that poing to lend him bail money.
And then, most of all, how gracefully and pleasantly she greets and embraces her brother, she having been convinced that he had been lost at sea in the shipwreck off the coast of Illyria. We then learn, when Orsino comes to realize that Viola really is a she, that he wants her for his wife and queen. What a pleasant and graceful love story this all is. That's our take.
Shakespeare knew how to make his women appealing to men.