Verbseoul.
하다 verb
실패하다silpaehadato fail (a task or action)

To say to fail (a task or action) politely in the present tense, use 실패해요 (sheel-pae-hae-yoh). Below is the full conjugation of 실패하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
실패해
sheel-pae-hae
실패해요
sheel-pae-hae-yoh
실패합니다
sheel-pae-hahm-nee-dah
Past
실패했어
sheel-pae-hae-ssuh
실패했어요
sheel-pae-hae-ssuh-yoh
실패했습니다
sheel-pae-hae-sseum-nee-dah
Future
실패할 거야
sheel-pae-hahl- -guh-yah
실패할 거예요
sheel-pae-hahl- -guh-yae-yoh
실패할 겁니다
sheel-pae-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
실패하세요
sheel-pae-hah-sae-yoh
Suggestion / Let's Polite (요)
실패해요
sheel-pae-hae-yoh
Question Polite (요)
실패해요?
sheel-pae-hae-yoh-?
Connective “and” — (고)
실패하고
sheel-pae-hah-goh
Conditional “if” — (면)
실패하면
sheel-pae-hah-myuhn
Noun form — (기)
실패함
sheel-pae-hahm