mutual understanding vs mutual affection

mutual understanding and mutual affection both are nouns.

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

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

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

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