How to Sign “Sure” in American Sign Language

The short answer

In American Sign Language (ASL), “sure” in the sense of “certain” is commonly signed by holding up your index finger near your lips and moving it forward, away from your mouth. The same sign is widely used for “true” and “really,” so context and facial expression tell the viewer which meaning you intend.

Two things can change this answer. First, this describes ASL, the sign language most used in the US. Other sign languages, such as British Sign Language, have their own signs, and this guide does not cover them. Second, English “sure” has more than one meaning. “I’m sure” (certain) and “Sure!” (okay, go ahead) are not always expressed the same way in ASL. Casual agreement is often shown with a nod, a sign for “okay” or “fine,” or other context-dependent choices, so the sign below fits the “certain” meaning best.

How to form the sign

• 1. Use your dominant hand, the one you write with.
• 2. Make the “1” handshape: index finger pointing up, other fingers curled into the palm, thumb resting over them.
• 3. Turn your palm to face sideways, toward your non-dominant side.
• 4. Place the side or tip of your index finger at or just in front of your lips or chin.
• 5. Move your hand straight forward and slightly down, away from your mouth, in one smooth motion.
• 6. Add a confident facial expression. A small nod or firm expression helps signal certainty.

Signers vary in exact placement and movement size, so you may see the finger start touching the lips or a short distance in front of them. Both are common. A more emphatic or repeated movement can add intensity, similar to saying “really sure” or “definitely.”

How to check that you’re signing it correctly

• Watch yourself in a mirror and confirm the handshape stays a single raised index finger throughout the movement.
• Compare your sign side by side with a video from a reputable ASL dictionary or a Deaf ASL instructor, paying attention to palm direction and where the movement starts.
• Ask a fluent signer to watch you. This is the most reliable check, because they can tell you whether the meaning comes across and whether your facial expression matches.

A mirror check confirms that your hand matches the description. It does not confirm that the sign reads naturally in conversation, or that you have chosen the right sign for the meaning you intend. Only feedback from fluent signers can confirm those.

Limits of this guide

No sign-language dictionary entries, videos or instructor notes were supplied for this article. The description above reflects commonly taught ASL usage, but you should confirm it against a trusted video source, especially because written descriptions cannot fully capture movement and facial grammar. Regional and personal variation exists within ASL, and local Deaf communities may prefer different signs for casual agreement. If you can’t recall the sign mid-conversation, fingerspelling the word is a fallback, though it is less natural than using a sign.