Set aside some quality time for the two of you to talk. This is a very private matter and you don't want to put him in an awkward position in front of other people. You should also work your way up to this serious conversation by talking about other deep matters first. It's important to make him feel comfortable and set the expectation that you two can share deep, personal feelings with each other. For example, talk about your family problems or maybe politics and your concerns for the future. Subtly bring up subjects that show him that you're okay with your friends being gay and that he doesn't need to hide his nature around you. You can talk about another friend that is gay or even just about someone hypothetically coming out if you don't know someone who's gay. For example, you can say something like "I really admire people like Neil Patrick Harris. He does a great job of showing people that there's more to gay people than all those offensive stereotypes. And he's clearly so happy now. I wish everyone felt like they could live as out and proud as he does." You can also talk about the experience that other people had with coming out. Show him that you're concerned that those same negative effects might plague him. This can show him that you're ready to be a support network if he needs one. Say something like, "Before Andie came out I was so worried about her. She seemed to be so unhappy...like she didn't like herself very much. And then everyone was so mean to her after she did. I don't want anyone to have to go through that." Now that you've set the precedent and shown him that you are someone safe and accepting to talk to, give him the time and opportunity to tell you. He might not tell you in that conversation. He might not even tell you that week. But if he is gay, he will probably tell you once he's comfortable and feels like he really trusts you. It is important to maintain an environment of trust if you want him to tell you. Don't spread any gossip about anybody, since spilling any kind of secret...

How would you rephrase that briefly using Vietnamese?
Tìm cơ hội nói chuyện riêng. Thể hiện sự ủng hộ nếu có bạn bè là người đồng tính. Nói về những người bạn khác đã thú nhận đồng tính. Cho họ cơ hội nói ra. Hỏi trực tiếp.