Certainly

a juro

(with certainty)

a todas luces

(without doubt, surely)

al cierto

(with certainty)

certeramente

(with certainty)

certeramente

(without doubt, surely)

ciertamente

(with certainty)

ciertamente

(without doubt, surely)

cierto

(with certainty)

de cierto

(with certainty)

de juro

(with certainty)

dejuramente

(with certainty)

dejuramente

(without doubt, surely)

en cierto (desus.)

(with certainty)

por supuesto

(emphatic affirmative answer)

sin duda

(without doubt, surely)