Yes. If honest was the following, then it would be easy: "Hey Jim, I happy to make the intro. But I don't think it makes sense now. My mentor is really busy and this project is still too young for him to be interested." But what if being honest was this: "Hey Jim, I have a ton of huge doubts about your project. To be honest, the idea seems silly and I don't know if you have the skills to execute it. If I suggested that my mentor spend time coaching you, it would reflect poorly on me. It would appear that I was wasting his time. That said, I know little about your project and industry. And I don't have the time required (right now) to intimately understand you and your startup." Is something like that too harsh?