By all means (hayhay, elbette, muhakkak)

You can take the book by all means.
Hayhay, kitabı alabilirsiniz.

Come early by all means. We'll be pleased.
Hayhay (elbette) erken geliniz. Memnun oluruz.

By all means, invite them as well.
Hayhay, onları da davet ediniz.