dare I say (it) [duplicate]
Dare is a semi-modal verb. The speaker can choose whether to use the auxiliary "to" when forming negative and interrogative sentences. For example, "I don't dare (to) go" and "I dare not go" are both correct. Similarly "Dare you go?" and "Do you dare (to) go?" are both correct.
Taken from the Wiktionary.
Note that when dare means challenge, it requires to, as in:
I challenge you to ask her out.
I dare you to ask her out.