Is it safer for a country to have many different allies or to rely on one very powerful relationship?

The question wether it is safer for a country to have many different allies or to have a singular reliable ally is quite controversial, as many factors come into play. Both sides have their pros and cons. Having a singular ally with whom a country has a strong relationship does not necessary correlate to a reliable ally, as is the case with USA or more specifically said, Trump. One would also not be as pressured to aid or support the ally in whatever campaign they are doing if you have a slightly weaker but more diversified relationship with multiple allies as your relationship isnt as developed. Ofcourse, all these argument besides my first one are all dependent on what terms you agreed to to create an alliance and what type of alliance it is. Im taking a defence alliance as an example in this case. Another thing to focus on is that having only a singular ally also means that if your alliance with said country does break, you wont have any other person to turn to, atleast until you develop a new relationship with another country.