What methods you want to use to spread sincerity and confidence between users and site owners in the site, so that users like to spend more time in the site?
This is a matter of culture-building (and definitely not a Feature ). The short answer is: Follow the Golden Rule:
One should treat others as one would like others to treat oneself.
Be sincere with your users and consistently reward sincerity and you’ll be well on your way to build a culture of sincerity in your community. For further reading, Art of Community would be a good start. It’s written by Jono Bacon, community manager for Canonical (Ubuntu).
Scroll to the bottom for a free PDF version.