Where does “vakuuttuminen” come from?

vakuuttuminen (Finnish) comes from Finnish vakuuttua, from Finnish vakuuttaa, from Finnish uuttaa, from Finnish uu, from Latin U, from Latin V, from Etruscan ? — u.

Ancestry of “vakuuttuminen”, step by step

Step	Language	Word	Meaning
1	Finnish	vakuuttua	To be convinced
2	Finnish	vakuuttaa	to assert, assure, convince; to reassure; to...
3	Finnish	uuttaa	to extract; Third-person singular indicative...
4	Finnish	uu	The name of the Latin-script letter U; hole, nest
5	Latin	U	—
6	Latin	V	ve
7	Etruscan	?	u

Every word from Etruscan ? →Every word from Latin V →Every word from Latin U →