how to make the smooth start and smooth end movements?
i tried to make the classic tween like the picture below, but when the movement reaches the middle keyframe, it doesn't looks sync with other keyframe. How do i deal with it?

It's either you stick with a 1 shot tween or you animate the V-CAM frame by frame.

Just do it Frame by frame, it looks better.

Quote from Zero

It's either you stick with a 1 shot tween or you animate the V-CAM frame by frame.

Just do it Frame by frame, it looks better.

Oh, okay then. Thanks for the help! :)

Use custom easing. If I think I know what you're talking about, It'll be perfect for the job.
http://prntscr.com/4zrfzq
See where it says "edit"? Click that and the custom easing menu/chart will show up.
http://prntscr.com/4zrgj0
(If you didn't know,)Use those 2 squares to manipulate the line to your liking. But keep in mind it correlates to the frame and percentage of tweening.
Based on the picture you have, it seems the type of tween line you want is this:
http://prntscr.com/4zrh3w
if you want to reset it, do NOT press the "reset" button, instead, make it 0 in the properties tab