mutual affection vs mutual understanding

mutual affection and mutual understanding both are nouns.

Word	Noun	Adjective	Verb	Adverb
mutual affection	Yes	No	No	No
mutual understanding	Yes	No	No	No

As nouns, mutual affection and mutual understanding are synonyms defined as:

mutual affection and mutual understanding: sympathy of each person for the other

mutual affection (noun)	mutual understanding (noun)
sympathy of each person for the other	sympathy of each person for the other