A lot of learners tell me the same thing: they have spent a fortune on English and still feel stuck. I have loved English since I was small, and I did not just want to learn it. I wanted to be the person who helps other people love it too.
The reality at my old language centre was different. I was rarely allowed to bring what I knew into the classroom. The promises the centre made to students, things like "we will teach extra hours if a student is struggling", were quietly dropped. When I offered to give a student extra support, it was refused on the spot: "That student isn't weak, why would they need help?"
What discouraged me most was how some teachers behaved behind students' backs, replaying a learner's pronunciation recording to laugh about it. When I said "they're here precisely because they haven't learned to pronounce it yet", I was the one seen as difficult. I left not long after, but I kept the goal of being a decent English teacher, and I still have it today.
So what actually matters?
For me, it comes down to two things: the teacher and the curriculum.
On the teacher side, I would look for at least IELTS 8.0 and a CELTA (Certificate in Teaching English to Speakers of Other Languages) from Cambridge.
CELTA is still unfamiliar to many people in Vietnam, where TESOL is the qualification that comes to mind first. Globally, though, CELTA is a well-regarded Cambridge certificate that covers teaching skills from the basics through to more advanced practice. Entry usually requires IELTS 7.5 or equivalent, plus two rounds of written and face-to-face assessment to check that the candidate is a fit for the course.
Even so, I think it is the teacher's professionalism and kindness that carries a learner to the finish line. However solid the curriculum, if the teacher lacks experience and cannot inspire anyone, it stays dry theory on paper.
That is why I keep sharing. I want you to find the motivation to learn English wherever you happen to be studying, and it does not have to be with me. I just want you to end up using the language comfortably.