It means "to be honest," and it is often used in
Facebook statuses. Another
definition is an "honest", yet all-too-flattering comment about a person that liked your status (offering a tbh) in order to receive the comment.
These posts are usually not very honest and I think
people would be much more honest if we still had the honesty box. The honesty box was anonymous, private, and as a result, extremely HONEST! Just call it the TBH Box and it will regain its popularity.
Example 1: Like for a tbh (Facebook status)
Example 2: Tbh the Beatles are a great
band. I hadn't heard of them before. (Facebook status)
Example 3: Tbh you are an awesome, caring, honest person and I think you're funny and hawt! We should talk more! (requested
Facebook wall post)