This is a regular verb. It follows the conjugation pattern of the verb hablar.
PresentPresente
Te juro que digo la verdad.
I swear to you that I am telling the truth.
PreteritePretérito indefinido
El testigo juró decir la verdad.
The witness swore to tell the truth.
FutureFuturo
El presidente jurará su cargo mañana.
The president will take the oath of office tomorrow.