Verbseoul.
하다 verb (adj)
감사하다gamsahadato be thankful

To say to be thankful politely in the present tense, use 감사해요 (gahm-sah-hae-yoh). Below is the full conjugation of 감사하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
감사해
gahm-sah-hae
감사해요
gahm-sah-hae-yoh
감사합니다
gahm-sah-hahm-nee-dah
Past
감사했어
gahm-sah-hae-ssuh
감사했어요
gahm-sah-hae-ssuh-yoh
감사했습니다
gahm-sah-hae-sseum-nee-dah
Future
감사할 거야
gahm-sah-hahl- -guh-yah
감사할 거예요
gahm-sah-hahl- -guh-yae-yoh
감사할 겁니다
gahm-sah-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
감사하세요
gahm-sah-hah-sae-yoh
Suggestion / Let's Polite (요)
감사해요
gahm-sah-hae-yoh
Question Polite (요)
감사해요?
gahm-sah-hae-yoh-?
Connective “and” — (고)
감사하고
gahm-sah-hah-goh
Conditional “if” — (면)
감사하면
gahm-sah-hah-myuhn
Noun form — (기)
감사함
gahm-sah-hahm