no cabe dudathere's no doubt about it
no tengo ninguna duda que…I have no doubt that…
si tienes alguna duda…if you have any questions…
poner algo en dudato call something into question
salir de dudasto set one's mind at ease
sin sombra de dudabeyond the shadow of a doubt
yo todavía tengo mis dudas sobre élI still have my doubts about him
tengo la duda de si he apagado la luz o noI'm not sure whether I turned off the light or not
tengo enormes dudas religiosasI have great religious doubts
al principio tuve muchas dudasI had a lot of misgivings or doubts at first