My contention is that we wouldn't want truth unless we secretly thought that the more truth we have, the happier we are.
Why should we think this? What if the more we realized truths, the more comprehensive our understanding of reality became (of ourselves, other people, the world, God or the lack of God), the more we realized how bad things really are?
It seems like we have a sort of faith-based optimism that at the end of the road of truth good things are in store. Otherwise, why would we equate truth with happiness; that is, consider truth the ultimate good?
I think this is a category error; a case can be made that truth is the highest quality from which all goods are derived. Choosing between truth and happiness is in this view would essentially be choosing between cause and effect.
Though I doubt he realized it at the time, Jack Nicholson as Col. Jessup in
A Few Good Men properly summed what I believe to be truth's greatest attribute (from a human point of view) as a repugnant, fearful thing when he grated at Tom Cruise through clenched teeth,
"You can't handle the truth!" I think this is true of Biblical or prescriptive (not factual) truth. The strength of Biblical truth is as metaphor, and the path to the good of greatest happiness (which in salvific terms
does lie at the end of the path, not very much on it) is through what truth does to us.
I agree that we don't want truth unless it bears fruit we like, which is why it's impossible for Christian salvation (i.e., eternal salvation) to be initiated by humans. Without going into tiresome proof texting, Jesus, as God, is truth as Willie T noted. It can be shown that metaphorically, truth is Godly fire. Godly fire is also hell, and it destroys only and ever evil. Never good. Jesus told us the world will be salted with fire (truth) which is a regenerational/sanctifying act (Jn 17:19). Since discomfort is associated with being burned by Godly fire--and the end result of being burned by Godly fire can be shown (again, allegorically) to result in purification
in the midst and process of destruction, the happiness associated with truth lies at the end of the road, not on it, as ValleyGal noted when she posted,
"I would not really view truth as bringing happiness. For me, truth has brought much pain, humility and the need for a Saviour. The truth hurts." Indeed it does, which is why so many of us sense that hell is experienced on earth.
Truth/Godly fire is now also both sanctification and regeneration, and as Col. Jessup noted, Christianity can't handle this truth because it leads to the higher, metaphorical truth that all will be saved
'yet so as through fire', as Paul puts it...and it takes away centuries of stuffy doctrines treating the various concepts noted above as though they're doctrines applied positively to some groups of humans while negatively to others.
So I agree with the idea in the op that the more truth we have, the more we see reality for the mess it is--which explains why we need the part of truth that burns like fire--which then provides reason to want (if not the will to actually seek) truth on the basis that its effects (happinesses) appear more down the road than in the here and now.