Remember that the promise of desire is the attainment of what you strive for, the promise of rejection is to not fall into what one would avoid, and that he who fails in his desires and falls into what he would avoid is unfortunate.
Our desire for or rejection of a thing, contrary to what most assume, is completely within our control, it belongs entirely to us. And what a mighty possession this is! The ability to choose what we desire and reject what we would avoid means that we have the power to withstand - even be content in - any situation. We can choose to want to happen whatever happens, and choose to reject the idea that anything is evil other than our own Vice (which, thanks to our sovereign power of choice, we also have the ability to eradicate from ourselves).
The Stoic lives according to Nature, and, recognizing that Virtue is according to Nature and that Vice and the Passions are against Nature, he chooses always to desire Virtue and reject the Passions. All the things that trouble other men - fear, lust, worry, anger, greed, and all else that truly harms us - cannot touch the Stoic. The Stoic is also a deeply pious man, yielding always to the will of the Universe, the will of God, wanting to happen whatever does happen. Thus, as a virtuous life cannot denied to him if he chooses to live virtuously, and as nothing ever occurs contrary to his own will (which he has conformed to the will of Providence), he can never fail to get what he wants, or to avoid what he does not want. The wise man is always happy.
But oh how unfortunate, how miserable and defenceless, is the man who desires that which he cannot control, who rejects things outside of his own self! Such a man is not God's follower, but God's slave! He must necessarily be unhappy, discontented, and anxious, waiting constantly in both hope and fear of every one of life's circumstances.