What is the verb form of amiable?

There isn't a direct verb form of "amiable." "Amiable" is an adjective describing someone who is friendly and pleasant.

To express the action of being amiable, you can use verbs like:

* Be friendly

* Be pleasant

* Show kindness

* Act in a cordial manner

* Be approachable

* Be agreeable

* Be sociable

For example, you could say: "She was friendly to everyone she met," or "He acted in a cordial manner towards his colleagues."