Is it true that I have to have proof if my neighbor touches my 5-year-old daughter?

If you wish to press some kind of charges against him you will need proof, yes.

Any time child molestation is suspected a report should be made to the police and to child protective services. The evidence or proof needed to make the report can be the statements of the child. Depending on the evaluation of the child to determine competency to testify will determine if more evidence is necessary to proceed to charges filed.

If she says that it happened that is proof.