Give up fantasy. Next sentence

Let's face it. "Abandoning fantasy" means that you no longer have hope or imagination for unrealistic or unattainable things. "Face reality" means to face up to the current actual situation, no matter whether they are good or bad. The whole meaning of these two sentences is to ask people to stop having illusions about unrealistic things, but to face up to the current reality, accept it and take positive actions to deal with it.