Word that means 'speak comfortingly/reassuringly'?

Is there an English word that means "to speak in a manner intended to comfort or reassure"? For example:

"Oh, honey, what's wrong?" her mother ____ed.

I keep wanting to say it is "croon", but Wiktionary insists that "croon" means "sing", and Thesaurus.com seems to agree based on what it considers acceptable synonyms.

"Cosset" is also in the neighborhood, but doesn't seem to imply speaking. "Console" is even closer, but doesn't really fit asking a question in such manner a la the above example.

(An answer with references that agrees with my intuition and can demonstrate that my sources are wrong is also acceptable.)

Edit: To clarify, an ideal answer would be a word that describes tone, such as "shout", "whisper", "hiss", etc., rather than a word that describes intent such as "placate", "assuage", etc. (the latter of which would otherwise be good answers).

Soothed

to bring comfort, solace, or reassurance to