How to say "we want what is best for our kids"?
我们要把最好的给我们的孩子

I think most Chinese parents would rather use this expression:
我们望子成龙

望子成龙 has this meaning: lit. to hope one's son becomes a dragon (idiom); fig. to long for one' s child to succeed in life; to have great hopes for one's offspring; to give one's child the best education as a career investment

It has more emphasis on succeeding in life, while "the best" is more open, and can also refer to happiness. This because most Chinese people have different values and aspirations for there children than most westerners (I'm generalizing here).