This depends on the activities you do on this forum with other members, an example of the trust you get from other members: https://bitcointalk.org/index.php?action=trust;u=2909527, if you trade or buy and sell Items on this forum you gain trust very fast.

the post you should leave like this: https://bitcointalk.org/index.php?action=profile;u=2909527;sa=showPosts;start=20 and which you have to upgrade like the members are here: https://bitcointalk.org/index.php?board=24.0

System (Merit) that answers this question.