To state something as true. (Cambridge Dictionary)
To publicly show your support for an opinion or idea. (Cambridge Dictionary)
Validate, confirm. (Merriam – Webster)
To state positively. (Merriam – Webster)
To assert (something, such as a judgment or decree) as valid or confirmed. (Merriam – Webster)
To show or express a strong belief in or dedication to (something, such as an important idea). (Merriam – Webster)
If you affirm that something is true or that something exists, you state firmly and publicly that it is true or exists. (Collins Dictionary)
State emphatically or publicly. (Oxford Dictionaries)
Declare one’s support for; uphold; defend. (Oxford Dictionaries)
Affirmation Law and Legal Definition.
Affirmations: The Why, What, How, and What If? – Psychology today.
The difference between ‘affirmation’ and ‘oath’.
What’s the difference between welcoming and affirming homosexuals?