故意に (koi ni: intentionally (usually knowingly), willfully)
The following sentences combine 故意 and に to create the sense of behaving badly with full knowledge of what one is doing:
彼は故意に間違った。
Kare wa koi ni machigatta.
He made a mistake on purpose.彼 (kare: he)
間違 (machiga(u): to make a mistake)
timing + difference彼女は故意に窓を壊した。
Kanojo wa koi ni mado o kowashita.
She broke the window on purpose.彼女 (kanojo: she) he + woman
窓 (mado: window)
壊 (kowa(su): to break, to break down)
彼は故意に嘘をついた。
Kare wa koi ni uso o tsuita.
He told deliberate lies.彼 (kare: he)
嘘 (uso: lie)