Simply replace the unfilled areas such as "__" and "_[date]_" with your information.
To Whom It May Concern:
_[name of babysitter]_ has been caring for our _[children/child]_ for _[length of time]_ now. _[He/She]_ has always been tremendously responsible, and our _[children/child]_ have always seemed to enjoy the time spent with _[his/her/their]_ babysitter. _[He/She]_ does not simply sit and watch television, ignoring our _[children/child]_, but always interacts and spends time with _[him/her/them]_.
_[name of babysitter]_ is kind, communicative, and trustworthy. We know that we can leave our _[children/child]_ in safety, and always enjoy the time we have out because of this.
In this day an age, it is very hard to find a dependable and honest sitter, so we very highly recommend _[name of babysitter]_ to you.