Question

믿을 수가 없군요 -(는)군(요), -(는)구나, -(는)구만/구먼(요) are three exclamatory endings applied to express surprise upon becoming aware about something by directly observing, experiencing, or by hearing about it from someone else for the first time. The endings correspond to various English exclamation patterns like 'indeed!', 'oh!', 'I see', 'how', 'it's really', 'my', 'gosh' and so on.Only -(는)군 and -(는)구만/구먼 can be used with the polite ending -요. The -(는)구나 ending belongs to the plain style (used, for example, when talking to yourself or when writing a diary). -(는)구만/구먼 is used in the familiar style.The -는 principle is required only in the case of verb stems in the present tense. All endings can occur preceded by the past or the future tense markers; additionally, the honorific -(으)시- can be applied.When used with the copula, endings change to -(이)군(요), -(이)구나, -(이)구만/구먼(요).

Accepted Answer

It's unbelievable!

Front	믿을 수가 없군요
Back	It's unbelievable!
Notes	-(는)군(요), -(는)구나, -(는)구만/구먼(요) are three exclamatory endings applied to express surprise upon becoming aware about something by directly observing, experiencing, or by hearing about it from someone else for the first time. The endings correspond to various English exclamation patterns like 'indeed!', 'oh!', 'I see', 'how', 'it's really', 'my', 'gosh' and so on. Only -(는)군 and -(는)구만/구먼 can be used with the polite ending -요. The -(는)구나 ending belongs to the plain style (used, for example, when talking to yourself or when writing a diary). -(는)구만/구먼 is used in the familiar style. The -는 principle is required only in the case of verb stems in the present tense. All endings can occur preceded by the past or the future tense markers; additionally, the honorific -(으)시- can be applied. When used with the copula, endings change to -(이)군(요), -(이)구나, -(이)구만/구먼(요).

Endings 는)구만/구먼 믿을 수가 없군요 Unbelievable 는)군(요 는)구나