Verbseoul.
하다 verb (adj)
행복하다haengbokhadato be happy

To say to be happy politely in the present tense, use 행복해요 (haeng-boh-kae-yoh). Below is the full conjugation of 행복하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
행복해
haeng-boh-kae
행복해요
haeng-boh-kae-yoh
행복합니다
haeng-boh-kahm-nee-dah
Past
행복했어
haeng-boh-kae-ssuh
행복했어요
haeng-boh-kae-ssuh-yoh
행복했습니다
haeng-boh-kae-sseum-nee-dah
Future
행복할 거야
haeng-boh-kahl- -guh-yah
행복할 거예요
haeng-boh-kahl- -guh-yae-yoh
행복할 겁니다
haeng-boh-kahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
행복하세요
haeng-boh-kah-sae-yoh
Suggestion / Let's Polite (요)
행복해요
haeng-boh-kae-yoh
Question Polite (요)
행복해요?
haeng-boh-kae-yoh-?
Connective “and” — (고)
행복하고
haeng-boh-kah-goh
Conditional “if” — (면)
행복하면
haeng-boh-kah-myuhn
Noun form — (기)
행복함
haeng-boh-kahm