Cuatro ojos ven más que dos or dos cabezas piensan mejor que una – four eyes see more than two eyes or two heads are better than one.
De la mano a la boca se pierde la sopa or del dicho al hecho hay mucho trecho – Easier said than done
El mandar no quiere par – Authority doesn’t want read more

Most often when you want to say that you are undecided the verb estar is used + indeciso/indecisa. For example, José está indeciso.. Joe is undecided or can’t decide.

However, there are a few Spanish idioms which express the same idea. Since the language is very idiomatic it is best to learn these forms in case you hear them used by a native read more