If they don't believe you, then to prove it you should be persistent is what I think she was saying.
I think continuing to try is fine but don't grab their arm/hand and or make stupid promises like I'll love you forever and i'll stay with you forever. Attacking gently I suppose?! It doesn't make sense though XD Oh well, I've been told that I'm confusing.
I don't think 'attacking' means exactly what it means to us. I don't think she meant it in the physical sense but to just keep confessing. Sometimes things just don't translate because of cultural nuances.
It took me forever to get the idea that "confessing " didn't mean taking responsibility for a guilty action. "Attacking" would translate more precisely to American English as "making a pass." Translating metaphor is weird.
I think you missed her point. What she's saying is that someone who is older will have a harder time taking a confession like that seriously from someone who is much younger, and so they have to prove that their like is sincere and genuine by being a bit more persistent about it. I felt that it wast solid advice.
i really didn't like the advice that the woman gave minami it's never good to "keep attacking them" or "be persistent" if a person doesn't like you they never will don't harass people