diff --git a/Source/Network/TextEncoding.cpp b/Source/Network/TextEncoding.cpp
index 6afb259f5..61aaa6824 100644
--- a/Source/Network/TextEncoding.cpp
+++ b/Source/Network/TextEncoding.cpp
@@ -160,7 +160,7 @@ std::wstring LowercaseWide(const std::string& text) {
 
 // OFFSET: 0x0058D6B0
 // FUNCTION: fn_02795
-int FindSubstring(const char* text, int codePage, const char* pattern) {
-  return static_cast<int>(LowercaseWide(text).find(LowercaseWide(pattern)));
+int FindSubstring(std::string_view text, std::string_view pattern) {
+  return static_cast<int>(LowercaseWide(text.data()).find(LowercaseWide(pattern.data())));
 }
 
diff --git a/Source/Network/TextEncoding.h b/Source/Network/TextEncoding.h
index 2acde88e6..8c58720fc 100644
--- a/Source/Network/TextEncoding.h
+++ b/Source/Network/TextEncoding.h
@@ -2,6 +2,7 @@
 #define RAGNAROK_SOURCE_NETWORK_TEXTENCODING_H
 
 #include <string>
+#include <string_view>
 #include <windows.h>
 
 extern UINT g_textCodePage;
@@ -14,7 +15,7 @@ std::string ToUtf8(const std::string& text, UINT codePage);
 
 void LowercaseText(std::string& text);
 std::wstring LowercaseWide(const std::string& text);
-int FindSubstring(const char* text, int codePage, const char* pattern);
+int FindSubstring(std::string_view text, std::string_view pattern);
 std::wstring DecodeText(UINT codePage, const std::string& text);
 std::string EncodeText(UINT codePage, const std::wstring& text);
 
diff --git a/Source/UI/ProbabilityTable/UIProbabilityTable.cpp b/Source/UI/ProbabilityTable/UIProbabilityTable.cpp
index e701cdd4b..ed79faceb 100644
--- a/Source/UI/ProbabilityTable/UIProbabilityTable.cpp
+++ b/Source/UI/ProbabilityTable/UIProbabilityTable.cpp
@@ -492,7 +492,7 @@ void CUIProbabilityTable::Search() {
 
   list = this->m_list;
   auto matches = [keyword](const ProbabilityTable::CItemData& data) {
-    return FindSubstring(data.name.c_str(), static_cast<int>(data.name.size()), keyword.data()) != -1;
+    return FindSubstring(data.name, keyword) != -1;
   };
 
   auto start = list->data.begin();
diff --git a/Source/UI/ProbabilityTable/UIProbabilityTableEvents.cpp b/Source/UI/ProbabilityTable/UIProbabilityTableEvents.cpp
index b63cdc2c4..eb3c2c30b 100644
--- a/Source/UI/ProbabilityTable/UIProbabilityTableEvents.cpp
+++ b/Source/UI/ProbabilityTable/UIProbabilityTableEvents.cpp
@@ -99,7 +99,7 @@ void CUIProbabilityTable::SetItem(int itemId) {
 // FUNCTION: fn_16210
 int HighlightKeyword(std::string& text, std::string_view keyword, std::string_view prefix, std::string_view suffix) {
   int count = 0;
-  if (FindSubstring(text.c_str(), static_cast<int>(text.size()), keyword.data()) == -1) {
+  if (FindSubstring(text, keyword) == -1) {
     return 0;
   }
 
diff --git a/Source/UI/Quest/UIRenewQuestUI.cpp b/Source/UI/Quest/UIRenewQuestUI.cpp
index 465ed9de6..daa040562 100644
--- a/Source/UI/Quest/UIRenewQuestUI.cpp
+++ b/Source/UI/Quest/UIRenewQuestUI.cpp
@@ -961,14 +961,7 @@ bool CUIRenewQuestUI::MatchesFilter(const RenewQuestInfo& info) const {
     return false;
   }
 
-  if (!this->searchText.empty()) {
-    if (FindSubstring(info.summary.c_str(), static_cast<int>(info.summary.size()), this->searchText.c_str()) == -1 &&
-        FindSubstring(info.m_title.c_str(), static_cast<int>(info.m_title.size()), this->searchText.c_str()) == -1) {
-      return false;
-    }
-  }
-
-  return true;
+  return this->searchText.empty() || FindSubstring(info.summary, this->searchText) != -1 || FindSubstring(info.m_title, this->searchText) != -1;
 }
 
 // OFFSET: 0x00A660E0