The state of comfort or ease; the degree to which something is pleasant or convenient.
新しいソファで部屋の快適さがぐっと増した。
The new sofa greatly increased the room's comfort.
出張では快適さを優先してホテルを選んだ。
For the business trip I prioritized comfort when choosing a hotel.
エアコンは夏の快適さに不可欠だ。
Air conditioning is essential for comfort in summer.