Translating near-illegible Roman inscriptions

I happened upon the following reply to the question
How do scholars translate text they only have fragments of?

The full question reads:

For example, in one of Trajan's monuments there is the following inscription:

MARTI ULTOR[I]IM[P(erator)CAES]AR DIVI NERVA[E] F(ILIUS) N[E]RVA TRA]IANUS [AUG(USTUS) GERM(ANICUS)] DAC]I[CU]S PONT(IFEX) MAX(IMUS) TRIB(UNICIA) POTEST(ATE) XIII IMP(ERATOR) VI CO(N)S(UL) V P(ater) P(atriae) ?VICTO EXERC]ITU D[ACORUM] ?---- ET SARMATA]RUM----]E 31.[2]

It seems to me that much of it is guess work, as many of the words are barely there.

The reply is by Astrogator.
Fascinating!