“Promise to do” is the standard pattern for committing to perform an action. The verb also occurs with noun objects and clauses, so those alternatives should be distinguished from a supposed direct gerund complement.
ReviewedEvidence2 sourcesSectionEnglish Usage
Quick answer
Use “promise to do” when committing yourself to an action. Direct “promise doing” is not the standard equivalent; “promise” also supports noun and clause patterns.
Key details
Confusion Familygrammar-and-usage distinction
Rule Familyverb complement pattern
TermsPromise Doing, Promise To Do
Further guidance
Decision
For a promised action expressed as a following verb, choose the to-infinitive.
Other Patterns
Promise also occurs with noun objects and content clauses; those are separate complement patterns rather than evidence for direct promise + -ing.
To Infinitive
Use promise + to-infinitive when the subject commits to performing an action.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
Cambridge documents both admit + -ing and admit to + -ing for acknowledging something. Other passive patterns such as “be admitted to be” are separate constructions.
Both patterns are standard. “Advise waiting” recommends an action generally or in context, while “advise him to wait” names the person who is advised to perform it. A that-clause is another standard option.
When “afford” is followed directly by another verb, standard learner references use a to-infinitive: “afford to do.” An -ing form can appear elsewhere in a sentence, but it is not a like-for-like direct complement after “afford.”
“Agree to do” expresses consent to take an action. An -ing form normally follows a preposition in patterns such as “agree with doing,” which expresses approval rather than the direct promise-to-act construction.
Cambridge documents aim + to-infinitive for intention and aim at for directing effort toward an objective. Do not omit the preposition and present bare “aim doing” as equivalent to “aim to do.”
“Allow” can take an activity as its object, as in “allow smoking,” or a person/thing followed by a to-infinitive, as in “allow visitors to enter.” The patterns answer different structural questions: what is allowed versus who is allowed to do what.
