The answer is patience, and you can find an illustration of it in Act II Scene IV, when Viola, disguised as the young Cesario, tells Orsino that her father's daughter (that is to say, herself) loved a man, and Orsino asks her about her story. This is what she says: "[...] She never told her love / But let concealment, like a worm i' the bud / Feed on her damask cheek: she pined in thought / And with a green and yellow melancholy / She sat like Patience on a monument / Smiling at grief. Was not this love indeed? [...]." Viola is here describing how, in spite of the profound love that she felt for a man (an allusion to her love for Orsino), a woman did not reveal it, and, instead, she sat and waited patiently, while her beauty went away and she became melancholic, pensive and heartbroken.