Hey!
I would probably avoid treating it exactly like a standard "why commercial law" question as it seems to be asking something slightly narrower - that is, why you wish to practise as a solicitor in an international firm environment, and how you have validated that interested.
The structure I would probably follow is along the lines of:
- Short introduction: discuss your overall motivation for becoming a solicitor and where international practice fits into that.
- Why the solicitor role: explain why the actual job appeals to you (e.g. client interaction, managing matters over time, coordinating parties, drafting/negotiation, helping clients implement solutions, and seeing work from start to finish).
- Why an international firm: explain why you want to do that work in an international environment specifically (e.g. cross-border matters, multinational clients, exposure to different markets, working across jurisdictions and teams, international commercial context, etc.).
- What steps you have taken to research: it is important to show how you tested these assumptions through conversations with lawyers, open days, vacation schemes, insight schemes, legal work experience, firm events, commercial reading, etc. I would focus on what each experience taught you rather than listing activities, and show how they confirmed your decision to pursue this route (for example, I always used to discuss my legal clinic experience confirming that I enjoyed the client interaction element of being a solicitor).
- Brief conclusion: explain how those experiences confirmed both the solicitor role and the international firm environment align with what you are looking for in your long-term career.
I hope that helps! I think this question is less about convincing them that international firms are interesting, and more about showing that you understand what is actually involved and how you have validated that you are interested in that.
Best of luck with the application
