There are a few errors but the right words...
First of all "suus filius" should be in the plural accusative. Plural beacuse sons is plural and accusative because the sentence is in Latin an indirect statement. Where we would say "I heard the girl is beautiful" the Latin would be "Audivi (puellam esse
)". Note the accusatives. A literal translation of that Latin is "I heard (the girl to be beautiful)" which is understandable in English. So infinitives, not the indicative mood of verbs are used for the indirect statement and necabant should be changed to the proper tense of infinitive necare. Err...
http://www.mythfolklore.net/medieval_la ... tement.htm
Undoubtedly clearer explanation of indirect statement
if that made no sense. Good luck! What are you translating this for by the way, school?