When Remus asked Tonks to marry him it was right after she yelled at him in the hospital wing in Hogwarts. She was right what does it matter how old he is, how much money he has or if he is a werewolf, Tonks loves him for him no other reason.
Remus found Tonks sitting next to the black lake with her head between her knees and her back shuddering meaning she was crying. He walks up to her and sits down next to her and puts his arm around her. "Your right Tonks it doesn't matter even if the cases are completely different. You love me and there is nothing that is going to change but I love you too."
Tonks looked up at Remus with her face tear stained and asks "Do you mean it? Or are you just telling me this to make me feel better?"
"Both because I hate seeing you up set. But I have one simple question for you."
"What question is that?"
"Will you Nymphadora Tonks marry me?"
Tonks stared at Remus for about 5 minuets then finally said "Yes."
Remus and Tonks both had big smiles on their face and Remus leaned down and kissed Tonks. Tonks felt the color flooding back to her and her hair turned her favorite shade of bubble gum pink.