Formal:
* ಗಂಭೀರವಾಗಿ (gambhīravaagi) - This literally translates to "seriously" and is the most common way to say it in formal contexts.
Informal:
* ಸರಿಯಾಗಿ (sariyaagi) - This means "correctly" or "properly," but is often used in informal situations to express seriousness.
* ನಿಜವಾಗಿಯೂ (nijavaagiyū) - This translates to "really" or "truly," and conveys a sense of disbelief or astonishment.
* ವಾಸ್ತವವಾಗಿ (vāstavaagi) - This means "actually" or "in reality," and can be used to emphasize the seriousness of a situation.
Other options:
* ಸಂಭಾಷಣೆಯನ್ನು ತೆಗೆದುಕೊಳ್ಳಬೇಡಿ (sanbhāṣaṇeyannu tegedukollabedi) - This means "don't take this conversation lightly," and is a more idiomatic way to convey seriousness.
* ನೀವು ಏನು ಹೇಳುತ್ತಿದ್ದೀರಿ ಎಂದು ನೀವು ಅರಿತುಕೊಂಡಿದ್ದೀರಾ? (nīvu ēnu hēḷuttiddīri endu nīvu aṛitukollondiddīra?) - This translates to "Do you realize what you're saying?," and can be used to express surprise or disbelief at something being said seriously.
The best way to say "seriously" in Kannada will depend on the specific context and the desired level of formality.