Question

what is the meaning of on the tip of ones tongue? i cant quite remember the name of that magician we saw perform in las vegas, but it is on the tip of my tongue. almost remembered a certainty

Explanation:

The phrase "on the tip of one's tongue" is an idiom. In the given sentence, the speaker can't remember the magician's name but feels it's very close to being recalled. "Almost remembered" fits this context as it implies the name is nearly retrieved from memory. "A certainty" doesn't match the meaning of the idiom.

Answer:

almost remembered