无非 (nothing but / merely)

Strip it down to the motive

• only无非wú fēi(to be / is是shì) + Verb / Noun = "nothing but / merely / no more than".
• he / him他tāso much这么zhè meto make做zuò，only无非wú fēito be / is是shìwant / think / miss想xiǎngto help帮bāngyou你nǐ = "he did this merely to help you."
• only无非wú fēi plays the matter down to one simple thing.

only无非wú fēi + to be / is是shì + Verb / Noun

• only无非wú fēi says it amounts to nothing more than X.

he他tāmerely无非wú fēiis是shìwant想xiǎnghelp帮bāngyou你nǐ。

• only无非wú fēito be / is是shìwant / think / miss想xiǎngto help帮bāngyou你nǐ = "(he) merely wants to help you."

Recap

Read the full reference: HSK 6 grammar — Adverbs.