These absolute infinitives frequently appear in most grammar books in Korea, but I doubt if they are actually used much in reality, especially "to be frank with you". Isn't "actully" more used than that? And what about the others?
gz115)
1.To tell (you) the truth
2. To begin with
3. To be frank (with you)
4. not to mention(=not to speak of)
5. to be sure
6. to make a long story short.

