As requested by anon. :)
“Kurosaki Ichigo, I have another very important speech to make to you. You must listen to me. I am going to explain why you should date my lieutenant, Renji. I have very good reasons.”
1. It was clear from the beginning how much Renji wanted you.
“Do you remember when the three of us met each other, Kurosaki Ichigo? Renji engaged you in combat and lost, the poor lamb. When I intervened on Renji’s behalf, he was upset. He told me that I did not have to help with a kid at your level. Those were his words, but I heard what he truly meant. He meant, ‘Captain, please don’t steal this hunk from me. I wish to claim him as my own.’”
2. He kept finding excuses to see you.
“And ever since that first moment, Renji has desired you carnally. You may have noticed how many excuses he found to see you when you first invaded Soul Society. He left a lieutenant’s meeting to confront you. He followed you to your 'secret’ hide-out and trained, shirtlessly, in your vicinity. He was trying to woo you, Kurosaki Ichigo. I am surprised that you were too dense to notice.”
3. He visited your dingy high school.
“Surely that is proof enough of his love. He put on a human uniform and came to your classroom. And yes, so did the rest of Captain Hitsugaya’s advance squad, but only Renji held you close while Rukia punched you. Once again, a clear sign of affection.”
4. Do I really need to point out all the times he’s followed you?
“To the world of the living. To Hueco Mundo. To the world of the living again. Whatever ill-planned adventure you embark on, Renji is sure to follow.”
5. The two of you have similar hair.
“I have already proved that Renji loves you. I suppose I must now show that the two of you are a good match. So I will begin with the most important factor: you have similar hair. Obnoxiously colored, spiky, messy but in a good way. Perhaps Renji could even teach you how to style yours.”
6. You both have a similar attitude.
“You and Renji both take a similar view of the world: you think it is best to rush headlong into things and just see how that goes. Then you get beat up, but you do not let that stop you. It is both noble and full of needless violence. The two of you can bond over that.”
7. You are flexible in your mindsets.
“Renji was one of the first officers of the Gotei-13 to join you, Kurosaki Ichigo. He realized that you were perhaps not such a bad man after all, and he went so far as to fight me in order to help you rescue Rukia. That shows a rare flexibility of mind. I believe you have a similar flexibility. You make friends with everyone, be they human or shinigami or visored or hollow. I believe that this is a quality you can appreciate in each other.”
8. Renji is smoking hot.
“He is a fine specimen of man. I’m sure that even someone as dense as you will have noticed, Kurosaki Ichigo.”
9. You both know how it is to be lied to by your powers.
“Both of you had powers that did not tell you the full truth - not until you were ready. Perhaps the two of you can bond over the fact that your own souls lie to you. Or cry about it, at least.”
10. You once climbed up to my window and burst through it shouting Renji’s name.
“And I may not know much about human courtship rituals (thankfully), but I am fairly certain that climbing up to a person’s window and shouting their name is something that a would-be lover does. So - to use a human phrase - get a room already. Preferably not mine.”