Verbseoul.
하다 verb (adj)
신비하다sinbihadamysterious

To say mysterious politely in the present tense, use 신비해요 (sheen-bee-hae-yoh). Below is the full conjugation of 신비하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
신비해
sheen-bee-hae
신비해요
sheen-bee-hae-yoh
신비합니다
sheen-bee-hahm-nee-dah
Past
신비했어
sheen-bee-hae-ssuh
신비했어요
sheen-bee-hae-ssuh-yoh
신비했습니다
sheen-bee-hae-sseum-nee-dah
Future
신비할 거야
sheen-bee-hahl- -guh-yah
신비할 거예요
sheen-bee-hahl- -guh-yae-yoh
신비할 겁니다
sheen-bee-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
신비하세요
sheen-bee-hah-sae-yoh
Suggestion / Let's Polite (요)
신비해요
sheen-bee-hae-yoh
Question Polite (요)
신비해요?
sheen-bee-hae-yoh-?
Connective “and” — (고)
신비하고
sheen-bee-hah-goh
Conditional “if” — (면)
신비하면
sheen-bee-hah-myuhn
Noun form — (기)
신비함
sheen-bee-hahm