Questions & Answers about Hän ei ole varma, tuleeko hän kokeeseen lauantaina.
The ending -ko / -kö is a question clitic. It turns the verb into a yes–no question.
- Direct question:
- Tuleeko hän? = Is he/she coming? / Will he/she come?
- Indirect (embedded) question:
- Hän ei ole varma, tuleeko hän... = He/She is not sure whether he/she will come...
In English you need a separate word (if, whether), but in Finnish you usually mark a yes–no question just by adding -ko/-kö to the verb, even inside another sentence.
In Finnish yes–no questions (including embedded ones) the conjugated verb with -ko/-kö usually comes first in its clause:
- Statement order: Hän tulee kokeeseen lauantaina.
- Question order: Tuleeko hän kokeeseen lauantaina?
When you embed that question after Hän ei ole varma, you keep the question word order:
- Hän ei ole varma, tuleeko hän kokeeseen lauantaina.
So: verb + -ko/-kö comes first, then the subject (hän), then the rest.