Frame Challenge (?)
I will try to synthesize an answer from the exchange I had in the comments with OP.
Short answer: No, your proposed reason, positive vs. negative adjective, is not the reason why the second sentence does not make sense. The main reason it doesn't make much sense logically.
If one considers negative adjectives that are more apt at describing a "bad reputation", then one can see it is word choice that is the problem and not negative vs. positive:
Nobody wants to be a student of this university because its bad reputation is detrimental for landing a job when graduating.
a bad reputation can be detrimental, a bad reputation is not easily described as difficult.
However, one can:
have a bad reputation of being difficult
but that would imply that the university is known for being difficult (probably in terms of unhelpful administration, bad advisers, complex financial systems) for students to endure.
One check is to make sure that the descriptor mostly makes sense when you remove the modifiers:
... because its good reputation is easy in landing a job (Incorrect)
A university's reputation being easy, used this way, doesn't make much sense. A way to rephrase this and still use easy is:
... because its good reputation makes it easy to land a job