Roberth sits next to 3 phonetic neighbors — Robert, Roberto, and Rupert are the closest matches by sound. Most share Roberth's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"bright fame"
"brave-hearted, bold spirit"
"the good one"
"gracious, favorable"
"God strengthens, strength of God"
"bearer of Christ"
"dim-sighted, unseeing"
"strength, power"
"beloved of God"
"little messenger of God"
"father of many"
"little one, beloved"
"victorious (if related to Cairo)"
"standing up again, reborn"
"powerful ruler"
"spear ruler (from Gerardo)"
"protector of men"
"flat-footed"
"sixth-born child"
Similar sound: These names share phonetic patterns with Roberth — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old High German origins, giving them the same cultural heritage as Roberth.
Rhythm: Roberth is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.