You just don`t get married on a blind date.
Clients need to trust you. They need to like you, and WANT you to be their Realtor.
You need to earn their trust.
When your new client requests to tour a home, present them with a Buyer broker that will expire in 14 days.
Two weeks is not that big of a commitment for your clients. You will have two weeks to find them a home. Ask the right questions, make sure the loan apps are done. Over that two weeks you will find out how serious your clients are.
When your two weeks are up. Present them with another two week commitment.
If you have earned their trust, around Buyer Broker 3 or 4, they will Tell you to make it for 90 or 180 days.