They value commitment
Loyalty has many definitions but one that makes the most sense is a commitment to your true love. Loyalty is a form of determination towards something, it can be love, a person, an institute, a hobby, just about everything.
A loyal person thinks that loyalty has to be committed to everything. If you find a person who stays committed to their daily life job, hobbies, or other things then it’s a good sign that they will remain loyal to the relationship with you as well.
A loyal person shows commitment not only to themselves, but they also portray it in other parts of their lives like relationships, dreams, and goals, pursuing a career, etc. They want that success in their lives and for that, they stay committed because of their burning desire for success.