Traduko - Portugala-Japana - Os noivos agradecem a presença

Romanized:
Hon-jitsu go-shusseki itadakimashite, watashi-tachi shinro-shinpu wa kokoro kara kansha shite orimasu.
Literally
Today, you have attended (our wedding), and we, the bride and the groom, humbly feel heartfelt gratitude.
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I realize this is quite long and there are a few other elements added, but this is as short as I could make it, in natural Japanese suitable for such an expression of gratitude, on such a _formal_ occasion. (Japanese is more "flowery"; you can't say things, _politely_, in as terse a way as in many Western languages.)