Daily Thai Confidence — Using มั่นใจ (mân-jāi)

Verb: มั่นใจ (mân-jāi)
Meaning: to be confident / to be certain / to be sure (about something)

In this Thai lesson, we learn how to use the verb มั่นใจ (mân-jāi), which means ‘to be confident,’ ‘to be certain,’ or ‘to be sure’ about something. It is used to talk about inner confidence — how sure you feel about information or facts, your decisions or choices, your ability or judgement. Since มั่นใจ (mân-jāi) is a verb, it must be placed after the subject of the sentence (ประธานของประโยค — bprà-t^hāan k^hǎwng bprà-yôok).

The typical structure usually follow the pattern: subject + มั่นใจ (mân-jāi) + complement (a clause or a prepositional phrase that completes the meaning of the verb).

For examples (ตัวอย่างเช่น — dtūa-^awyàang chên)

chǎn mân-jāi wâa chǎn rīan p^hāa-sǎa Thāi dâi
Literal: I confident that I learn language Thai can.
I’m confident that I can learn Thai.

The complement marker ว่า (wâa) means ‘that’ and is used to introduce the complement clause and to link the verb มั่นใจ (mân-jāi = to be confident / to be certain / to be sure) to the clause that completes its meaning.

chǎn mân-jāi nāi gāan-dtàd-sǐn-jāi k^hǎwng-chǎn
Literal: I confident in the act of deciding belonging to-me.
I’m confident in my decision.

The preposition ใน (nāi) means ‘in’ and is used to introduce the noun phrase การตัดสินใจของฉัน (gāan-dtàd-sǐn-jāi k^hǎwng-chǎn = my decision). Together, they form a prepositional phrase that completes the meaning of the verb มั่นใจ (mân-jāi = to be confident / to be certain / to be sure).

k^hǎo mân-jāi nāi bprà-sòb-gāan k^hǎwng dtūa-āeng
Literal: He confident in experience belonging to oneself.
He is confident in his own experience.

The preposition ใน (nāi) means ‘in’ and is used to introduce the noun phrase ประสบการณ์ของตัวเอง (bprà-sòb-gāan k^hǎwng dtūa-āeng = one’s own experience). Together, they form a prepositional phrase that completes the meaning of the verb มั่นใจ (mân-jāi = to be confident / to be certain / to be sure).

k^hrūu mân-jāi wâa nák-rīan t^húk-k^hōn k^hâo-jāi
Literal: Teacher confident that student every-person understand.
The teacher is confident that all the students understand.

The complement marker ว่า (wâa) means ‘that’ and is used to introduce the complement clause and to link the verb มั่นใจ (mân-jāi = to be confident / to be certain / to be sure) to the clause that completes its meaning.

Practise putting your newly learned Thai word into a sentence by translating the following sentences below.

1. They are confident in our decision.
2. He is confident in the books he had chosen to read.
3. We are sure that the meeting will start on time.
4. I am confident that he can handle this situation.
5. I am confident that I will be able to finish this homework by tomorrow.

About Post Author

Urai Khomkham

Hi, I’m Urai Khomkham, a Thai language teacher and the creator of Thai Language Tuition UK. I help learners understand how Thai really works, so they can stop guessing and start feeling confident using the language in real life. Inside the community, I share clear lessons, practical explanations, and gentle guidance to support steady, meaningful progress — without pressure or overwhelm. I also share free Thai lessons and learning tips on my YouTube channel, where I break things down step by step and help you build strong foundations at your own pace. By subscribing, you’re not only supporting your own learning — you’re also helping me continue creating free resources to support you and other learners on their Thai journey.

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