"長い間誰かと付き合っていれば、とてもよくお互いを知ることになると思います。良い時も悪い時も、個人的なことも関係内のことも、一緒に乗り越えていきます。"

Simplified Meaning:

When you spend a long time with someone, like in a relationship, you really get to understand them deeply. You see not only their best moments but also when things aren't going so well. Imagine a couple who has been together for many years. They've celebrated happy occasions like birthdays and holidays, but they've also faced tough times, such as job losses or family issues. Through all these experiences, they learn each other's strengths and weaknesses, what makes the other laugh or cry, and how to support each other. This shared journey creates a strong bond because they have seen each other in every situation and still choose to stay together. For someone in a relationship, it's a reminder that both good and bad moments are essential for building a deeply connected and resilient partnership.