How do I construct an Il2Cpp string?

Using Il2CppDumper, I have dumped my files and am perusing the methods and their arguments using dnSpy. Some methods take string arguments like this one:

[Token(Token = "0x6000338")]
[Address(RVA = "0xE89871", Offset = "0xE88671", VA = "0x180E89871", Slot = "5")]
public Task<GameObject> SpawnPhoto(string photo)
{
    return null;
}

Hooking into this function using Minhook, I cannot simply intercept the function, and then modify the string like this before executing the function:

void(__fastcall* spawn_photo)(const char*);
void __stdcall spawn_photo_hook(const char* photo)
{
    photo = "some string";
    
    return spawn_photo(photo);
}

This causes the application to crash when the function is called. What is the minimal code that I need to construct an Il2Cpp string that I can pass to the function before executing it?