信 (Kanji for believe)

Onyomi

SHIN

If they've got a SHINy halo, it's safe to believe what that person has to say .

しん*じる

believe
★★★★★

自信(じしん)

self-confidence ★★★★☆
自 (my own) + 信 (believe) = 自信 (self-confidence)

信号(しんごう)

signal ★★★★☆
信 (believe) + 号 (ID number) = 信号 (signal)

signal, i.e. traffic signal

迷信(めいしん)

superstition ★★★☆☆
迷 (perplexed) + 信 (believe) = 迷信 (superstition)