some guys want to take it slow because they like you and Don't want to lose you. the hard fact is that if a guy wants to sleep with you right away chances are all he wanted was to make a deposit in your bank then go- wanted your body only. also some are old fashioned and want to be proper
To drag it out and make the excitement last longer. When I was dating my now-wife we took it slow, one step at a time, it was like being in high school again! Plus a guy should do that anyway just to be a gentleman.
Because it is respectable and they really like you. But don't just assume it either. Not only that, if he says he wants to take things slow always watch his actions they must match in with what he speaks.