Should I date this guy!?

Basically, I've started meeting up with this guy but all my other friends have told me he's a sleeze. I knew he was a few years back but he's told me he's changed. My bestfriend (whos a guy) has told me that he's obviously rather cunning and he said that this guy shouldn't just be nice to me because he likes him, but he should be nice to me all the time. My bestfriend said that if I'm having doubts now that it's going to be extremely hard to trust him when yous are together. This guy has told me that he's slept with 4 people already this year so I'm abit concered. I think I like him but I'm so unsure what to do!! Help please!