Cras , vos quod vestri sanctimonialis mos have lost severus orsa of juvenis.
Is what I think it is, but it'd be better if you checked your resourced to make sure.
Where in the world did you study Latin? If you cannot correctly answer the question, it's best that you don't post at all. Please!
Isolate these things in the English sentence:
Everything else is a modifier of one of these. Subject goes first in the sentence and needs to be in nominative case.
Verb goes last in the sentence and needs to be in the 3rd plural form, future perfect tense.
Direct object and its modifiers go just in front of the verb. Cras is the correct word for "tomorrow," and having it at the beginning of the sentence, but would be better nearer the verb.
Give it a try, and repost.
I don't have the vocab with me for harsh begginings of youth. however i know that harsh begginings should be in the accusative form and of youth should be genative. so far i have
cras tu tuusque sora amiterint
is any of that correcT?
Cras - correct
tu - correct
That's about it!
sister = soror -- now to find the adjective form of "your" and make it agree with soror. Join the two subjects with et.
beginnings = orsa, orsorum (neuter plural)
See this for help with declensions and conjugations:
I do best when I have a very good Latin-English dictionary/grammar in my hands. These websites can help you in the meantime.
Tu et soror tua orsa severa juventus (<~~long mark over that u before the s) cras perdiderint.
Tu et soror tua = you and your sister
orsa severa = harsh beginnings
juventus = of youth
cras perdiderint = tomorrow will have lost.