returning sidespin

No it isn't easy in the beginning, just get the feel for the ball, and try to do side spin the opposite direction of your opponent (usually combined with backspin). Or do the Waldner trick, don't do any side spin back, just use the side spin of your opponent to get the ball where you want. That requires some experience, but is very effective. Good luck!

thanks guys i`ll try put into practice what you say tonight

For returning sidespin, I have a rule that works for me and my students,
     Whatever direction the bat was going at contact, that is the direction the ball will try to go when you hit it.
     This works with serves or any other hit.
     Bat going down, (chop) it will try to go low
     Bat going up (topspin) it will try to go high
     Bat going up and to your left, it will go up and to your left when you return.
     Example: if I see a shot that his bat was going up and to my left, I just aim to the right and deal with the top like any other shot.