Trust is a delicate thing. Putting your trust in someone who isn't worthy of it can lead to disappointment and hurt. On the other hand, a healthy level of trust is essential for meaningful relationships.
Observing consistency, as actions consistently align with their words. They are there when they say they will be...!

Evaluate if they are honest with you? They share openly with you, even when it's uncomfortable. They uphold their values, even when no one is watching.
Check that they respect your boundaries and listen to your concerns. They show empathy and understanding towards you and others.

See the communication is effective and they are open to having difficult conversations. They listen to you without interrupting or judging.
Do they provide They support you in your endeavors and offer help when needed. They accept you for who you are without judgment.
Trust is built over time through shared experiences and mutual respect. No one is perfect, but a trustworthy person makes an effort to be consistent, honest, respectful, communicative, and supportive.