Altruism makes some sense to me as an answer... if you're choosing to sacrifice your own happiness in order to be more effective at improving the world, and believing true things makes you more effective at improving the world, then that's coherent.

Unrelatedly, if the problem is social alienation, one approach is to find a community in which the things you want to do (including believe true things) are socially acceptable.

If you did feel that believing true things made you unhappy, would you try to make yourself belief not-true but satisfying things?

There are areas in which I focus my attention on useful and probably false beliefs, like "I can make a significant difference in the world if I choose to take action." It's not clear to be that I believe those things, though. It's also not clear to me that it matters whether I believe them or not, if they are motivating my behavior just the same.