Going by your title, I think its too early to judge that Arjun makes her stronger. Anjali is the kind of person who is self-motivated to take on challenges. She doesn't need another to motivate her or challenge her. She is similar to Arjun that way. Both of them compete with themselves even though they appear to compete with others.
I think all of them will learn from each other. Anjali, too, has a lot to learn from Arjun, & so does Arjun, Akaash & everyone else who is part of this journey.