Answer:
Increase.
Step-by-step explanation:
In the sentence "All of these......confidence", the verb used is 'increase', as it defines the action in the sentence. Verbs are that part of speech that heads the predicate and they are introduced into the sentence to cipher the mood or voice. There are different types of verbs including the "transitive", "Intransitive", "Ditransitive", etc. In the given sentence "increase" is the word that conveys the action of "All of these things" on to the "Self-confidence". Thus, this is the verb.