Several parts combine into one character.

實 (traditional) combines 宀 (house) with 貫 (a string of coins) inside — a house (宀) filled with wealth (貫), hence "to be full, fruit, true, reality." From a storehouse full of grain and goods grew "substance, the real."

The form splits three ways: traditional (ko/en/es) is 實, Japanese shinjitai (ja) is 実 (the bottom reduced to 大), Chinese simplified (zh) is 实 — different by mode (實 14 strokes vs 実 / 实 8).

Korean hanja-sound "sil": 實際 (silje, actuality), 事實 (sasil, fact), 現實 (hyeonsil, reality), 眞實 (jinsil, truth), 誠實 (seongsil, sincerity), 實力 (sillyeok, ability), 果實 (gwasil, fruit). Korea uses the traditional 實.

Mandarin: shí, 2nd tone. 实际 (shíjì, actual), 事实 (shìshí, fact), 现实 (xiànshí, reality), 真实 (zhēnshí, true), 实力 (shílì, strength), 其实 (qíshí, actually). 其实 (qíshí, actually) is a daily Mandarin essential.

Japanese: on-reading ジツ (jitsu), kun み (mi), みの.る (minoru), まこと (makoto). 実際 (jissai, actuality), 事実 (jijitsu, fact), 現実 (genjitsu, reality), 実力 (jitsuryoku, ability), 果実 (kajitsu, fruit), 実る (minoru, to bear fruit). The kun み means "fruit, kernel" — 木の実 (konomi, tree fruit).

Memory aid: a house (宀) full of wealth (貫) — a character that splits into traditional 實 / shinjitai 実 / simplified 实.