You’ve got to ask if you want to make the sale. It’s basic business practice. After presenting your product, you ask them to buy. A salesperson who never asks the customer to commit will not make sales. Though what we are doing is not business, the principle applies. If you never ask people to commit to following Christ, you will make very few (if any) disciples.
We can not let fear prevent us from asking people to commit. After sharing a gospel presentation, testimony, or praying for someone, you must ask. You must extend the invitation.