If he'll lie to someone else, he'll lie to you. If he scouts out girls to be in the wings, he'll scout while he's with you too.
What do you think dating is? If it's just playing around doing what feels good at the time, then do whatever you want, but that's a dangerous game with potentially life changing consequences.
If dating is evaluating men for the characteristics you want in a lifelong committed relationship, then wait a few years. The boys your age are often like Bob the Fickle, charming but immature, and opportunistic. When they get older, some of them grow up, and by then you'll be wiser too, about what characteristics you want in a MAN, (not a boy)
Respect for you, respect for others, dependable, hard working, good sense of humor, moral, reasonably sanitary, has a job/career, kind, not judgemental, not demanding or manipulative....
Take some time to think about the characteristics YOU want. And do not ever date a guy a second time if there are things about him you think you could change. You can't change anyone, so don't settle for someone who doesn't meet the criteria. You have lots of time, believe it or not, so spend a lot of your energies working on your skills and your career possiblities, so that someday when you do hook up with the right guy, you'll do so because you're a match, and not because you're feeling desperate for someone to take care of you.
Sorry, too much advice from someone you don't know. But there it is. Good luck to you!
(Do you ever wonder if your friend's parents who said "no" know something you girls don't?)