Crying is not a weakness nor a strength. Crying is an emotion.
You cannot judge someone on basis of it. One cries due to stress which can be physical, mental or emotional. But the sad phase comes for a time. For example: If someone who is going through a tough time seems happy at a moment, you may say they are strong. They may just be managing their emotions.
Men and women both can cry. No one is weak. In fact, crying helps to release emotions and balance the stress hormones.
The body makes several types of tears. Pain, sadness, sorrow, joy, happiness and memories. You don’t have to wait until you’re alone. As long as it’s not due to stress and/or depression, but even then it’s ok. But if the problem is truly mental, then a doctor should be talked to, so that needed meds may be given to help.
It takes guts to show your feelings than to pretend you don’t have any. Don’t be afraid to cry. There is no right or wrong.