"To the stars through difficulties" is an English translation of the Latin motto "Ad astra per aspera".
As you can see, the Latin phrase is rather nicely formed; short and alliterative. The English translation is not very poetic.
It is the motto of many institutions, including the US state of Kansas, NASA and many countries' air forces.
- "astra"; "the stars" signifies aspirations, glory, better things. Of course when used by NASA and air forces, is is slightly more literal.
- "aspera"; "difficulty", "hardships", meaning problems we pass through on the way
Like many mottos, it is not really a full sentence in English. There is an implied extra part:
(I/we aim to get) to the stars through difficulties
"Through difficult to defeat" is not correct.
If you mean "(I aim to) tolerate hardships in order to eventually defeat (something)" then the following are acceptable English sentences:
- Through difficulties to victory
- Through difficulty to victory
- Through hardships to victory
- Through hardship to victory
However none of them are well known phrases.
Be careful with "defeat".
- "Joshua led his army to defeat the Egyptians" - means Joshua won (defeat is a verb)
- "Napoleon led his army to defeat" - means Napoleon lost (defeat is a noun)