Perception is interesting. Trust is fickle.
I often offer prospective clients a second 1-hour call focused on goal-setting and coaching, if we have chemistry and it seems that you have goals I will be able to help you reach based on a first call.
The "free" coaching of the second call is sometimes met with skepticism.
It's not free - I'm actually interviewing you, because I'm fortunate enough to have reached a point that I can chose clients. That extra "free" hour is to make sure that I want to work with you (for six months or longer). And it's more than worth my time.
Yes, I have delivered career-transforming coaching in one "free" hour with no resulting sale. But I'm happy to do that for the personal peace of mind that if I sign you up as a client that I will be great for you, you will be a great client, and our sessions will leave me energized and ready to serve my other clients.