How to stop player velocity completely

I have made a script that makes the character move. The problem is that the character is sliding around. I want to set velocity to 0 anytime the right buttons arent pressed. What line of could could do that. Thanks for any guidance and explaining. Herses the code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Movement : MonoBehaviour
 {
     private bool moving;
 
     [SerializeField]
     Vector3 v3Force;
 
     [SerializeField]
     KeyCode keyPositive;
 
     [SerializeField]
     KeyCode keyNegative;
 
     void FixedUpdate()
     {
         if (Input.GetKey(keyPositive) || Input.GetKey(keyNegative))
         {
             moving = true;
         }
         else { moving = false; }
 
         if (moving)
         {
             if (Input.GetKey(keyPositive))
                 GetComponent<Rigidbody>().velocity += v3Force;
 
             if (Input.GetKey(keyNegative))
                 GetComponent<Rigidbody>().velocity -= v3Force;
         }
         else 
         {
             
         }
     }
 }