Translation:You are the only reason I have to finish college.
Sei . . . . , l'unico . , motivo, che, ho . . . , per finire, l'università.
You are, the only, reason , that, I have, to finish , the university.
Whoa... this is quite the powerful sentence for me... Is this romantic love? Admiration? Close friendship?
"the reason why I have to finish" can have a different meaning, in English, from "the reason I have to finish the university."
"The reason why I have to finish" - in this case, "why I have to" means "why I must."
"… the reason I have to finish . . . " could mean the same thing, but it's more likely to be understood as "you are my motivation."
[Native US English speaker]
This sentence does not translate quite well into English. It doesn't make much sense.