en_tn/mrk/08/12.md

He sighed deeply in his spirit

This means that he groaned or that he let out a long deep breath that could be heard. It probably shows Jesus' deep sadness that the Pharisees refused to believe him. See how you translated this in Mark 7:34.

in his spirit

"in himself"

Why does this generation seek for a sign?

Jesus is scolding them. This question may be written as a statement. AT: "This generation should not seek a sign." (See: rc://en/ta/man/translate/figs-rquestion)

this generation

When Jesus speaks of "this generation," he is referring to the people who lived at that time. There Pharisees are included in this group. AT: "you and the people of this generation" (See: rc://en/ta/man/translate/figs-explicit)

no sign will be given

This can be stated in active form. AT: "I will not give a sign" (See: rc://en/ta/man/translate/figs-activepassive)