Yeah i dont understand men?

he has been hitting on me recently and pretty fast i might add. he respects my boundaries and everything, and tells me that he wont do anything that i feel uncomfortable with and sticks to his word, but he always tells me about how he finds me attractive, how he'll always back me up, and how he sees me as distinct, special, and different/sweeter than other girls and i dont know why i have such a hard time believing all his flattery. its just kind of fast dont you think? i mean we havent talked for 2 years and we started talking again recently and hes already trying to move in again like he did before. i just dont know what his intentions are. i mean do boys ever just try to get a female to fall for her just for fun and then leave her? just for the heck of it? boys help me out here and let me know how i can ever tell if a guy is being genuine. or if hes just spitting game or being a sneaky jerk. once again, i do not understand men much *sigh*.