undertake

(verb) enter upon an activity or enterprise. Synonyms: set about, attempt.

(verb) accept as a challenge. Synonyms: tackle, take on. Examples: "I'll tackle this difficult task."

(verb) promise to do or accomplish. Synonyms: guarantee. Examples: "Guarantee to free the prisoners."

(verb) enter into a contractual arrangement. Synonyms: contract.

(verb) accept as a charge. Synonyms: take in charge.