How should I translate "in truth, beauty" to Latin? It is similar to how in vino veritas means "in wine, truth." I don't know much about Latin and Google Translate wasn't very helpful. It suggested vero forma, but this didn't translate back to English properly.
Google Translate is horrible with Latin, and this is yet another piece of evidence. The correct way to translate by analogy is to understand the structure and replace the words. Google Translate seems to be incapable of this, which is bewildering. The suggested translation seems to have nothing to do with what you wanted.
In the phrase in vino veritas ("truth [is] in wine") we have "wine" in ablative and "truth" in nominative. To translate "beauty [is] in truth", we need "beauty" in nominative and "truth" in ablative. (The word "is", est, is often left implicit in Latin, and Latin word order is different from English. Therefore I find "truth is in wine" or "there is truth in wine" to be an accurate translation of in vino veritas.)
Especially if you want to do something similar to the well known Latin quote, veritas is a good choice for "truth". There are a couple of options for "beauty", and I suggest starting with pulchritudo and amoenitas (coming from pulcher and amoenus). You can check the two words in any online Latin dictionary and compare how the translations back to English differ. For a quick comparison, I would say that a person can be pulcher and a scenery can be amoenus.
Depending on what kind of beauty you mean, I suggest: In veritate pulchritudo/amoenitas.