Tell you what. If a 10 year old can come to you and describe a sex act in any form done to her by an adult you would be wise to listen. Number one look for fear. Many kids will not tell even a parent because a threat has been made to harm them, the childs parent, a sibling, a pet, or yes even the perp says I will kill myself if you tell anyone what happened. They demeanor of the kid is what you look at.
If the kids says so and so made me touch him someplace. Ask where that was. Then ask them to describe visually what they touched. Don't be surprised if they say I can't I wasn't looking. Ask then about what it felt like and the kid can likely descibe the persons organ and some functions it did during the assault. {enough said I think you get the idea}. The perps many times have their victim focus on an object not allowing visual contact while the deed takes place. But they can describe feel senses. Find that object and watch the childs reaction to it. It will most likely be a stuffed animal. Use some common sense and the truth likely will come out.
Assuming all kids lie about abuse is just as bad as assuming no child ever lies about abuse.