This is the 812th most frequent Serbian word.
сасвим
"Сасвим" means "completely" or "entirely" in English.
In this sentence, 'сасвим' is used as an adverb meaning 'completely' or 'entirely', emphasizing the newness of the book.
Ова књига је сасвим нова.
This book is completely new.
Here, 'сасвим' indicates that the action of asking for help is entirely acceptable, showing approval.
Сасвим је у реду да питаш за помоћ.
It's entirely okay to ask for help.
In this context, 'сасвим' again emphasizes the adverbial use, meaning 'completely' to stress the difference.