Search product api response irrelevalant to search string

[kuldi]

I am trying to integrate a storefront search product api. But the response I get from searched keyword is irrelevant. Suppose if I enter a 'Bracelets' keyword as a search parameter then I get the correct response related to bracelets. But if I search 'Bangles' keyword then I get an Irrelevant response, even though I have a bangles products in my store. I am Using API query listed below.

query{

          products(first: 250, query: "title: $searchString" ) {

              edges {

                    node {

                        id

                        title

                       priceRange{

                            minVariantPrice{

                            currencyCode

                            amount

                      }

           }

          metafield(key:"rating_count", namespace:"reviews" ){

          value

      }

      featuredImage{

       url

     }

   }

}

}

}