満足 and 充実: satisfaction, substantial content, and a fulfilling day
Compare satisfaction with a completed work or meal to a substantial library collection and a fulfilling day. Distinguish a person's response from the content described without inventing complete coverage or universal satisfaction.
Responses to a work and a meal with 満足
満足 (まんぞく) describes satisfaction with something. 「丁寧に仕上がった作品に満足した。」 reports satisfaction with a carefully completed work.
「少ない材料でも十分に満足できる食事だった。」 describes a meal that could be fully satisfying despite having few ingredients. Read 「少ない材料でも」 with 「十分に」: few ingredients do not mean that the meal could not be satisfying.
A substantial collection and a fulfilling day with 充実
充実 (じゅうじつ) describes content that is substantial or fulfilling. In 「図書館の資料が充実していて調査しやすいです。」, the library's substantial collection makes research easy, but the sentence gives neither an exact count nor a guarantee that every needed resource is available.
「友人と学びながら充実した一日を過ごしました。」 describes spending a fulfilling day learning with a friend. A fulfilling day can include a sense of personal reward, so 充実 is not limited to having many physical items in stock.
A response and the content that may support it
The work example focuses on a satisfied response to that work, whereas the library example focuses on resources that support research. A substantial collection does not establish that every user was satisfied; identify the response or the content actually described.
A fulfilling day may carry a subjective sense of reward, so 満足 and 充実 do not form an absolute division between emotion and objective quantity. Their meanings can overlap while still drawing attention to a person's satisfaction or the content of resources and time.
Does a library collection described as 充実している contain every needed resource and satisfy every user?
Show the answer and why
The example does not establish either claim. It says that the collection is substantial and makes research easy, without giving complete coverage or every user's response. The state of the collection should not be substituted for universal satisfaction.