verbs with adjectival function?

Question

In the sentence "忘れられない夜にする" does the verb "忘れる" have the function of an adjective? What is the meaning of the phrase? Is there any way to make verbs have a Japanese adjectival function?

Answer 1

does verb "忘れる" have the function of an adjective - You usually call it an embedded clause, or a relative clause (in English grammar). The meaning is: the night that I cannot forget. But you are right, technically it serves as an adjective, is this case as an i-adjective.

is there any way to make Verbs have a Japanese adjective function? - Every clause in short form can work in that way, as any clause ends with a verb. Something more complicated: 家族と住んでいる家 - the house in which I live with my family, uses the clause 家族と住んでいる - I live with my family, as embedded clause.

Answer 2

in sentence "忘れられない夜にする" does verb "忘れる" have the function of an adjective?

Yes, because it is modifying a noun. The meaning of it here is as if the English adjective "unforgettable".

What is the meaning of the phrase?

It means "Make this an unforgettable evening". The "ni suru" part means "make this". Who is making it so depends on context but usually that would be the speaker.

is there any way to make Verbs have a Japanese adjective function?

Your question seems to answer itself - you have a verb modifying a noun as if it is like the English adjective "unforgettable" - "an unforgettable evening".