Pathos is a mode of persuasion that aims to convince an audience on something by making an emotional appeal, usually by evoking strong emotions like pity, fear, disgust, sorrow, sympathy, or hope. Most of the time, when pathos is used, the writing or speech does not hold any evidence that supports its content, it usually lacks the use of logic and reason.
The sentence "Because you deserve the best" is an example of pathos because it lacks evidence that supports why "you" deserve it, and intends to evoke an emotion or feeling in the reader.