Where does “Selbstzweifel” come from?

Selbstzweifel (German) comes from German Zweifel, from Middle High German zwīvel, from Old High German zwīfal, from Proto-West Germanic twīfl, from Proto-Germanic twīflaz, from Proto-Indo-European dwóh₁ — two.

Selbstzweifel (German): self-doubt

Definitions

self-doubt

Ancestry of “Selbstzweifel”, step by step

Selbstzweifel traces back through two separate lines of ancestry.

via German Zweifel

Step	Language	Word	Meaning
1	German	Zweifel	doubt
2	Middle High German	zwīvel	—
3	Old High German	zwīfal	two-fold
4	Proto-West Germanic	twīfl	doubt
5	Proto-Germanic	twīflaz	doubt
6	Proto-Indo-European	dwóh₁	two

via German selbst

Step	Language	Word	Meaning
1	German	selbst	personally, by oneself; even
2	Old High German	selb	—
3	Proto-Germanic	selbaz	self
4	Proto-Indo-European	selbʰ-	one's own
5	Proto-Indo-European	s(w)e-	separate, apart; separate; apart; oneself; one's...
6	Proto-Indo-European	swé	self

Every word from Proto-Indo-European dwóh₁ →Every word from Proto-Germanic twīflaz →Every word from Proto-West Germanic twīfl →