Naruto saw Ino crying and felt that there was someone who cared about him. And Naruto felt bad seeing Sakura sad and thought he had to get to far stronger if he wanted to bring Sasuke back to the village for Sakura.
Few days later Naruto got discharged and started completing mission with other squad. There were missions when Naruto and Ino were together. They started getting closer, spending more time, they were bold to each other and called blond duo.
Jiraya decided to go on a journey along training session with Naruto.
Naruto: Without Ino this time too? Right,
Jiraya: Yeah! This time for two/three years,
Naruto: What? Why?
Jiraya: Why? Don't you want to get stronger, find Sasuke?
Naruto: Yeah but,
Jiraya: No more talk. I'll wait for you at village gate tomorrow morning. You have some time left, Go and spend it with your girlfriend.
Naruto: What? (Blushing), she is not my girlfriend. (Inner voice: Not yet or should I say, I don't know how she feels about me, Even I don't know WHAT are my feelings for her?)
As Naruto tries to argue with his own feelings Jiraya smiles and went out of Naruto's House and feel proud as Grandfather.
As day pass, Naruto meets everyone except Ino because he does not wanted to make Ino sad, he can't say goodbye to her.
Next day morning, it was time for Naruto's departure Jiraya, Naruto and Tsunade were checking their backpacks that if there is something missing.
Ino came running and hit Naruto in his head and started yelling at him for not telling her about his leave.
He apologizes and tells Ino that this time it may take 2 or 3 years.
Her eyes get teary and she said to herself, "so not seeing each other for two/three whole years."
He said that he will send letters to her sometimes and she can always come to him whenever she wants.
Jiraya says that they will not set their hold in one place of a long time and they will never know where they will go after either so meeting will not be possible for them as her letters can not sent to an unknown places.
Naruto apologizes again that they can't talk to each other even with letters. He promises and says he will come back to her
She nods.
Jiraya: It's time for our departure and goodbye Tsuna, We will come soon after investigation ends.
Naruto: Goodbye Ino, See you soon.
Both master and student leave after saying goodbye to their counterparts.
(Naruto Shippuden)
Few years later Ino collected a pile of letters from Naruto sitting at her store counter recalling her days with Naruto and yawned while looking at outside.
Naruto: Ah! It's been so long to be in the village.
Jiraya: Your training is complete and now you are back in the village, did you tell your girlfriend about your return?
Naruto: No. I wanted to give a little surprise to her.
Jiraya: So, you accept that she is your girlfriend.
Naruto (blushes): N-No, we are NOT couples. We are just really good friends.
Jiraya: You always send letters to her, telling about your journey and she is not your girlfriend. I thought only couples/lovers do that.
Naruto: And what about you? You always send letters to Grandma Tsunade.
Jiraya (sigh): Those are not letters. Those are reports on Orochimaru's hideout and about your training.
Naruto: Well, You always talked about her like me as I always talks about Ino. And she always talks about you how similar we are and I remind her of you.
Jiraya: Yeah, we spent a lot of time together as we were on same team and I started liking her not knowing when.
Naruto: Have you ever proposed to her?
Jiraya (sigh again): Every time I proposed every time I get rejected.
Naruto tried to say something but Jiraya said "Rejection makes a man stronger, do not fear about rejection. Snatch the opportunity to tell your feeling to someone you love."
Naruto: What.... If our friendship ends!
Jiraya: If you are close enough to understand each other then no.
Naruto: Can I also propose to Ino?
Jiraya: Yeah. You can. And we are back in the village. Go surprise you girl and I am gonna report to my Hokage girl.
Naruto: Good luck, Pervy Sage.
Jiraya: Good luck to you too and stop calling me by that name.
Naruto left and rushes to Ino's Flower Shop without getting home and unpacking his backpack.
Ino (yawning and dosing off, looking at the ceiling): I'm getting bored no missions, no customers, no friends to hang out because everyone else is on the mission. And Naruto is still not coming back.
Someone: Do you have red roses? I want to surprise my girlfriend.
Ino: Yeah. It is on the right side of that table. (Pointing on the table full of different type of roses)
Naruto picks up a bunch of roses and try to hide his face.
Naruto: Ino, May I ask your hand for marriage?
Ino looks to the man grabbing a bouquet full of roses and thinks "Another boy proposing me"
Ino: Nope, Not gonna do, I already reject every boy in this village. And you're another boy proposing me.
Naruto: Are you gonna still reject me even if I show you my face.
Siding bouquet and showing his face to Ino. She jumped on Naruto and said, How am I gonna reject someone who I am already fell in love with.
They suddenly realised that they are not dating right now and gets embarrassed.
Naruto: I didn't think you were in love with me.
Ino: I didn't think as well. I missed you idiot.
Naruto: I missed you too.
Ino: Will you stay for lunch?
Naruto: I don't think I can, granny summons me and master to the office so I won't be able to come for lunch.
Ino: Then how about dinner? We'll get your favourite ramen from the shop.