I hate these types of spots as I think most do, but I try to put my opponent on a hand obviously. The ranges that I would put villain on genearlly aren't going to include the hands that have us beaten here (although with an unknown its much harder to say). AA,KK,QQ villain is going to be raising before we do, or surely repopping us, 44 I can't see villain calling our raise and set mining because it seems too high a price. QK seems to be the most likely to me, but again I don't see his line being very normal here.
I like to call the all in here, and if by some freak of nature he is sitting on the KQ we still have aces and diamonds to catch.
Looks fine, given the two diamonds. If the board was drier I might check the flop, but giving a free card here would be pretty bad. There are plenty of draws a random could make this play with.