Player Respawn and Kill C# Skript Erro

l am getin a erro:error CS0029: Cannot implicitly convert type int’ to bool

Here is my code:

using UnityEngine;
 using System.Collections;
 
 public class Die : MonoBehaviour {
 
     public int lives = 1;    
 
     public GameObject Player = GameObject.FindGameObjectWithTag("Player");
 
     // Use this for initialization
     void Start () {
 
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 
     void OnTriggerEnter2D(Collider2D col){
         lives--;
         if (col.gameObject.tag == "Spike") {
             lives = -1;
         }
         if (lives = -1) {
             transform.localPosition =new Vector2(-3.78,1.84);
             lives = 1;
         }
         }
     }

Change lines #25-26 to this:

    if (lives == -1) {
        transform.localPosition = new Vector2(-3.78f, 1.84f);