Ask HN: How to get users to test a product without sounding like I am selling?

I am spending my time developing a free tool for developers.

The tool is entirely free, not gated by login walls or anything like that.

I know with a high degree of confidence that the vast majority of the users that I approach are my target audience, i.e. they have the need for the exact service that I am asking them to test.

I know this mostly because it is a very well defined circle of people (QA engineers beginning to learn specific software) and because it has a high-level of stickiness for people who do end up trying it.

My problem though is the initial reach out. It seems like no matter how I try to wrangle the conversation, the receiving person thinks that I am trying to get them to buy something.

I approach every lead in a private Slack server, through 1:1s. A typical conversation goes something like this:

me: Hey, welcome to X. How good is your Y?

them: Hey! I am a complete noob

me: Let me know if I can help you answering any of your questions.

them: Thanks. Will do!

Up to this point the conversation is Okay.

Now it seems no matter how I introduce the product next, this is where the other person feels swindled, e.g. I will say: "I've built a X tool which can answer your questions as a novice. Would you be up to try it?" or simply "Have you already heard of X? It can answer..." only about 3 in 10 say they want to try it.

One could argue that I should build up the conversation more, but that is neither scalable, nor do I want to waste their time.

Would love to hear from HN crowd on what would increase my odds of engagement.