I think would be surrogate mother's motives to enable sterile couple to have a baby are praiseworhty

.===>I think the motive of the surrogate mother in helping the sterile couple to have a baby is praiseworthy.

 However if she will be paid as what the contract says, it makes the meaning less meaningful because it's not a labor of love.

===>However if she will be paid as what was being agreed on the contract, it only makes it meaningless for it's not a labor of love.

And also nothing happens with 100% probabilities.

===>And also, we can't  guarantee a 100% probabilities.

So the details of how it will be handled are being considered in a contract, like when surrogates don't want to give up the child or children are less than perfect, natural parents get divorced etc..

===>So the details on how it will be handled are being considered in a contract,like when the surrogate won't give up the child, and if the child will be less than perfect,or even if the natural parents will get divorced,etc..

The baby will be confused about his or her identity just when knowing the truth.

===>The baby will be confused of his/her identity right after knowing the truth. 

Anyway natural parents can get a baby that they really want with the help of a surrogate mother.

===>Anyways, the natural parents can have a baby that they've been wishing for with the help of a surrogate mother.

We should think seriously about how happy that baby is.

===>But we should think seriously about the baby's happiness as well.