You can now start sending this new member with advertising paraphernalia such as newsletters, brochures, and catalogues that he can use mailing list in deciding to purchase something from you. But keep in mind not to overdo it or it might annoy him which leads to unsubscribing from you. Give him enough time and space to decide on his own.
Follow up only after a reasonable amount of time has elapsed. In essence, earning the trust of your client should not be impossible especially mailing list if what you offer him is really beneficial on his side. Trust is gained and maintained if your client sees that you really know what you are talking and promoting about. Experience can also help in getting the trust of people because you can personally prove them why your business is worth it.
Honesty is a vital component in gaining trust from the customers. If your customer sees that you are honest with them, they will admire you for mailing list that and patronize your business religiously. Never dare to tell them anything that is not true just to gain publicity because in the long run, the truth will come out and when it does, it will hit your business very hard.