What is "creia"

Question

What is "creía"? I have the conversation phrase here-> "Disculpe, creía que estaba sola."

Answer 1

It's the imperfect past-tense of "creer".

"Excuse me, I [or someone] thought you [or someone else] were alone."

If you look up creer in the dictionary, you can find it in the verb conjugation chart.